1 /*
   2  * Copyright (c) 2001, 2015, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 #include "precompiled.hpp"
  26 #include "classfile/metadataOnStackMark.hpp"
  27 #include "classfile/stringTable.hpp"
  28 #include "code/codeCache.hpp"
  29 #include "code/icBuffer.hpp"
  30 #include "gc/g1/bufferingOopClosure.hpp"
  31 #include "gc/g1/concurrentG1Refine.hpp"
  32 #include "gc/g1/concurrentG1RefineThread.hpp"
  33 #include "gc/g1/concurrentMarkThread.inline.hpp"
  34 #include "gc/g1/g1Allocator.inline.hpp"
  35 #include "gc/g1/g1CollectedHeap.inline.hpp"
  36 #include "gc/g1/g1CollectorPolicy.hpp"
  37 #include "gc/g1/g1CollectorState.hpp"
  38 #include "gc/g1/g1ErgoVerbose.hpp"
  39 #include "gc/g1/g1EvacFailure.hpp"
  40 #include "gc/g1/g1GCPhaseTimes.hpp"
  41 #include "gc/g1/g1Log.hpp"
  42 #include "gc/g1/g1MarkSweep.hpp"
  43 #include "gc/g1/g1OopClosures.inline.hpp"
  44 #include "gc/g1/g1ParScanThreadState.inline.hpp"
  45 #include "gc/g1/g1RegionToSpaceMapper.hpp"
  46 #include "gc/g1/g1RemSet.inline.hpp"
  47 #include "gc/g1/g1RootProcessor.hpp"
  48 #include "gc/g1/g1StringDedup.hpp"
  49 #include "gc/g1/g1YCTypes.hpp"
  50 #include "gc/g1/heapRegion.inline.hpp"
  51 #include "gc/g1/heapRegionRemSet.hpp"
  52 #include "gc/g1/heapRegionSet.inline.hpp"
  53 #include "gc/g1/suspendibleThreadSet.hpp"
  54 #include "gc/g1/vm_operations_g1.hpp"
  55 #include "gc/shared/gcHeapSummary.hpp"
  56 #include "gc/shared/gcLocker.inline.hpp"
  57 #include "gc/shared/gcTimer.hpp"
  58 #include "gc/shared/gcTrace.hpp"
  59 #include "gc/shared/gcTraceTime.hpp"
  60 #include "gc/shared/generationSpec.hpp"
  61 #include "gc/shared/isGCActiveMark.hpp"
  62 #include "gc/shared/referenceProcessor.hpp"
  63 #include "gc/shared/taskqueue.inline.hpp"
  64 #include "memory/allocation.hpp"
  65 #include "memory/iterator.hpp"
  66 #include "oops/oop.inline.hpp"
  67 #include "runtime/atomic.inline.hpp"
  68 #include "runtime/init.hpp"
  69 #include "runtime/orderAccess.inline.hpp"
  70 #include "runtime/vmThread.hpp"
  71 #include "utilities/globalDefinitions.hpp"
  72 #include "utilities/stack.inline.hpp"
  73 
  74 size_t G1CollectedHeap::_humongous_object_threshold_in_words = 0;
  75 
  76 // INVARIANTS/NOTES
  77 //
  78 // All allocation activity covered by the G1CollectedHeap interface is
  79 // serialized by acquiring the HeapLock.  This happens in mem_allocate
  80 // and allocate_new_tlab, which are the "entry" points to the
  81 // allocation code from the rest of the JVM.  (Note that this does not
  82 // apply to TLAB allocation, which is not part of this interface: it
  83 // is done by clients of this interface.)
  84 
  85 // Local to this file.
  86 
  87 class RefineCardTableEntryClosure: public CardTableEntryClosure {
  88   bool _concurrent;
  89 public:
  90   RefineCardTableEntryClosure() : _concurrent(true) { }
  91 
  92   bool do_card_ptr(jbyte* card_ptr, uint worker_i) {
  93     bool oops_into_cset = G1CollectedHeap::heap()->g1_rem_set()->refine_card(card_ptr, worker_i, false);
  94     // This path is executed by the concurrent refine or mutator threads,
  95     // concurrently, and so we do not care if card_ptr contains references
  96     // that point into the collection set.
  97     assert(!oops_into_cset, "should be");
  98 
  99     if (_concurrent && SuspendibleThreadSet::should_yield()) {
 100       // Caller will actually yield.
 101       return false;
 102     }
 103     // Otherwise, we finished successfully; return true.
 104     return true;
 105   }
 106 
 107   void set_concurrent(bool b) { _concurrent = b; }
 108 };
 109 
 110 
 111 class RedirtyLoggedCardTableEntryClosure : public CardTableEntryClosure {
 112  private:
 113   size_t _num_processed;
 114 
 115  public:
 116   RedirtyLoggedCardTableEntryClosure() : CardTableEntryClosure(), _num_processed(0) { }
 117 
 118   bool do_card_ptr(jbyte* card_ptr, uint worker_i) {
 119     *card_ptr = CardTableModRefBS::dirty_card_val();
 120     _num_processed++;
 121     return true;
 122   }
 123 
 124   size_t num_processed() const { return _num_processed; }
 125 };
 126 
 127 YoungList::YoungList(G1CollectedHeap* g1h) :
 128     _g1h(g1h), _head(NULL), _length(0), _last_sampled_rs_lengths(0),
 129     _survivor_head(NULL), _survivor_tail(NULL), _survivor_length(0) {
 130   guarantee(check_list_empty(false), "just making sure...");
 131 }
 132 
 133 void YoungList::push_region(HeapRegion *hr) {
 134   assert(!hr->is_young(), "should not already be young");
 135   assert(hr->get_next_young_region() == NULL, "cause it should!");
 136 
 137   hr->set_next_young_region(_head);
 138   _head = hr;
 139 
 140   _g1h->g1_policy()->set_region_eden(hr, (int) _length);
 141   ++_length;
 142 }
 143 
 144 void YoungList::add_survivor_region(HeapRegion* hr) {
 145   assert(hr->is_survivor(), "should be flagged as survivor region");
 146   assert(hr->get_next_young_region() == NULL, "cause it should!");
 147 
 148   hr->set_next_young_region(_survivor_head);
 149   if (_survivor_head == NULL) {
 150     _survivor_tail = hr;
 151   }
 152   _survivor_head = hr;
 153   ++_survivor_length;
 154 }
 155 
 156 void YoungList::empty_list(HeapRegion* list) {
 157   while (list != NULL) {
 158     HeapRegion* next = list->get_next_young_region();
 159     list->set_next_young_region(NULL);
 160     list->uninstall_surv_rate_group();
 161     // This is called before a Full GC and all the non-empty /
 162     // non-humongous regions at the end of the Full GC will end up as
 163     // old anyway.
 164     list->set_old();
 165     list = next;
 166   }
 167 }
 168 
 169 void YoungList::empty_list() {
 170   assert(check_list_well_formed(), "young list should be well formed");
 171 
 172   empty_list(_head);
 173   _head = NULL;
 174   _length = 0;
 175 
 176   empty_list(_survivor_head);
 177   _survivor_head = NULL;
 178   _survivor_tail = NULL;
 179   _survivor_length = 0;
 180 
 181   _last_sampled_rs_lengths = 0;
 182 
 183   assert(check_list_empty(false), "just making sure...");
 184 }
 185 
 186 bool YoungList::check_list_well_formed() {
 187   bool ret = true;
 188 
 189   uint length = 0;
 190   HeapRegion* curr = _head;
 191   HeapRegion* last = NULL;
 192   while (curr != NULL) {
 193     if (!curr->is_young()) {
 194       gclog_or_tty->print_cr("### YOUNG REGION " PTR_FORMAT "-" PTR_FORMAT " "
 195                              "incorrectly tagged (y: %d, surv: %d)",
 196                              p2i(curr->bottom()), p2i(curr->end()),
 197                              curr->is_young(), curr->is_survivor());
 198       ret = false;
 199     }
 200     ++length;
 201     last = curr;
 202     curr = curr->get_next_young_region();
 203   }
 204   ret = ret && (length == _length);
 205 
 206   if (!ret) {
 207     gclog_or_tty->print_cr("### YOUNG LIST seems not well formed!");
 208     gclog_or_tty->print_cr("###   list has %u entries, _length is %u",
 209                            length, _length);
 210   }
 211 
 212   return ret;
 213 }
 214 
 215 bool YoungList::check_list_empty(bool check_sample) {
 216   bool ret = true;
 217 
 218   if (_length != 0) {
 219     gclog_or_tty->print_cr("### YOUNG LIST should have 0 length, not %u",
 220                   _length);
 221     ret = false;
 222   }
 223   if (check_sample && _last_sampled_rs_lengths != 0) {
 224     gclog_or_tty->print_cr("### YOUNG LIST has non-zero last sampled RS lengths");
 225     ret = false;
 226   }
 227   if (_head != NULL) {
 228     gclog_or_tty->print_cr("### YOUNG LIST does not have a NULL head");
 229     ret = false;
 230   }
 231   if (!ret) {
 232     gclog_or_tty->print_cr("### YOUNG LIST does not seem empty");
 233   }
 234 
 235   return ret;
 236 }
 237 
 238 void
 239 YoungList::rs_length_sampling_init() {
 240   _sampled_rs_lengths = 0;
 241   _curr               = _head;
 242 }
 243 
 244 bool
 245 YoungList::rs_length_sampling_more() {
 246   return _curr != NULL;
 247 }
 248 
 249 void
 250 YoungList::rs_length_sampling_next() {
 251   assert( _curr != NULL, "invariant" );
 252   size_t rs_length = _curr->rem_set()->occupied();
 253 
 254   _sampled_rs_lengths += rs_length;
 255 
 256   // The current region may not yet have been added to the
 257   // incremental collection set (it gets added when it is
 258   // retired as the current allocation region).
 259   if (_curr->in_collection_set()) {
 260     // Update the collection set policy information for this region
 261     _g1h->g1_policy()->update_incremental_cset_info(_curr, rs_length);
 262   }
 263 
 264   _curr = _curr->get_next_young_region();
 265   if (_curr == NULL) {
 266     _last_sampled_rs_lengths = _sampled_rs_lengths;
 267     // gclog_or_tty->print_cr("last sampled RS lengths = %d", _last_sampled_rs_lengths);
 268   }
 269 }
 270 
 271 void
 272 YoungList::reset_auxilary_lists() {
 273   guarantee( is_empty(), "young list should be empty" );
 274   assert(check_list_well_formed(), "young list should be well formed");
 275 
 276   // Add survivor regions to SurvRateGroup.
 277   _g1h->g1_policy()->note_start_adding_survivor_regions();
 278   _g1h->g1_policy()->finished_recalculating_age_indexes(true /* is_survivors */);
 279 
 280   int young_index_in_cset = 0;
 281   for (HeapRegion* curr = _survivor_head;
 282        curr != NULL;
 283        curr = curr->get_next_young_region()) {
 284     _g1h->g1_policy()->set_region_survivor(curr, young_index_in_cset);
 285 
 286     // The region is a non-empty survivor so let's add it to
 287     // the incremental collection set for the next evacuation
 288     // pause.
 289     _g1h->g1_policy()->add_region_to_incremental_cset_rhs(curr);
 290     young_index_in_cset += 1;
 291   }
 292   assert((uint) young_index_in_cset == _survivor_length, "post-condition");
 293   _g1h->g1_policy()->note_stop_adding_survivor_regions();
 294 
 295   _head   = _survivor_head;
 296   _length = _survivor_length;
 297   if (_survivor_head != NULL) {
 298     assert(_survivor_tail != NULL, "cause it shouldn't be");
 299     assert(_survivor_length > 0, "invariant");
 300     _survivor_tail->set_next_young_region(NULL);
 301   }
 302 
 303   // Don't clear the survivor list handles until the start of
 304   // the next evacuation pause - we need it in order to re-tag
 305   // the survivor regions from this evacuation pause as 'young'
 306   // at the start of the next.
 307 
 308   _g1h->g1_policy()->finished_recalculating_age_indexes(false /* is_survivors */);
 309 
 310   assert(check_list_well_formed(), "young list should be well formed");
 311 }
 312 
 313 void YoungList::print() {
 314   HeapRegion* lists[] = {_head,   _survivor_head};
 315   const char* names[] = {"YOUNG", "SURVIVOR"};
 316 
 317   for (uint list = 0; list < ARRAY_SIZE(lists); ++list) {
 318     gclog_or_tty->print_cr("%s LIST CONTENTS", names[list]);
 319     HeapRegion *curr = lists[list];
 320     if (curr == NULL)
 321       gclog_or_tty->print_cr("  empty");
 322     while (curr != NULL) {
 323       gclog_or_tty->print_cr("  " HR_FORMAT ", P: " PTR_FORMAT ", N: " PTR_FORMAT ", age: %4d",
 324                              HR_FORMAT_PARAMS(curr),
 325                              p2i(curr->prev_top_at_mark_start()),
 326                              p2i(curr->next_top_at_mark_start()),
 327                              curr->age_in_surv_rate_group_cond());
 328       curr = curr->get_next_young_region();
 329     }
 330   }
 331 
 332   gclog_or_tty->cr();
 333 }
 334 
 335 void G1RegionMappingChangedListener::reset_from_card_cache(uint start_idx, size_t num_regions) {
 336   HeapRegionRemSet::invalidate_from_card_cache(start_idx, num_regions);
 337 }
 338 
 339 void G1RegionMappingChangedListener::on_commit(uint start_idx, size_t num_regions, bool zero_filled) {
 340   // The from card cache is not the memory that is actually committed. So we cannot
 341   // take advantage of the zero_filled parameter.
 342   reset_from_card_cache(start_idx, num_regions);
 343 }
 344 
 345 void G1CollectedHeap::push_dirty_cards_region(HeapRegion* hr)
 346 {
 347   // Claim the right to put the region on the dirty cards region list
 348   // by installing a self pointer.
 349   HeapRegion* next = hr->get_next_dirty_cards_region();
 350   if (next == NULL) {
 351     HeapRegion* res = (HeapRegion*)
 352       Atomic::cmpxchg_ptr(hr, hr->next_dirty_cards_region_addr(),
 353                           NULL);
 354     if (res == NULL) {
 355       HeapRegion* head;
 356       do {
 357         // Put the region to the dirty cards region list.
 358         head = _dirty_cards_region_list;
 359         next = (HeapRegion*)
 360           Atomic::cmpxchg_ptr(hr, &_dirty_cards_region_list, head);
 361         if (next == head) {
 362           assert(hr->get_next_dirty_cards_region() == hr,
 363                  "hr->get_next_dirty_cards_region() != hr");
 364           if (next == NULL) {
 365             // The last region in the list points to itself.
 366             hr->set_next_dirty_cards_region(hr);
 367           } else {
 368             hr->set_next_dirty_cards_region(next);
 369           }
 370         }
 371       } while (next != head);
 372     }
 373   }
 374 }
 375 
 376 HeapRegion* G1CollectedHeap::pop_dirty_cards_region()
 377 {
 378   HeapRegion* head;
 379   HeapRegion* hr;
 380   do {
 381     head = _dirty_cards_region_list;
 382     if (head == NULL) {
 383       return NULL;
 384     }
 385     HeapRegion* new_head = head->get_next_dirty_cards_region();
 386     if (head == new_head) {
 387       // The last region.
 388       new_head = NULL;
 389     }
 390     hr = (HeapRegion*)Atomic::cmpxchg_ptr(new_head, &_dirty_cards_region_list,
 391                                           head);
 392   } while (hr != head);
 393   assert(hr != NULL, "invariant");
 394   hr->set_next_dirty_cards_region(NULL);
 395   return hr;
 396 }
 397 
 398 // Returns true if the reference points to an object that
 399 // can move in an incremental collection.
 400 bool G1CollectedHeap::is_scavengable(const void* p) {
 401   HeapRegion* hr = heap_region_containing(p);
 402   return !hr->is_pinned();
 403 }
 404 
 405 // Private methods.
 406 
 407 HeapRegion*
 408 G1CollectedHeap::new_region_try_secondary_free_list(bool is_old) {
 409   MutexLockerEx x(SecondaryFreeList_lock, Mutex::_no_safepoint_check_flag);
 410   while (!_secondary_free_list.is_empty() || free_regions_coming()) {
 411     if (!_secondary_free_list.is_empty()) {
 412       if (G1ConcRegionFreeingVerbose) {
 413         gclog_or_tty->print_cr("G1ConcRegionFreeing [region alloc] : "
 414                                "secondary_free_list has %u entries",
 415                                _secondary_free_list.length());
 416       }
 417       // It looks as if there are free regions available on the
 418       // secondary_free_list. Let's move them to the free_list and try
 419       // again to allocate from it.
 420       append_secondary_free_list();
 421 
 422       assert(_hrm.num_free_regions() > 0, "if the secondary_free_list was not "
 423              "empty we should have moved at least one entry to the free_list");
 424       HeapRegion* res = _hrm.allocate_free_region(is_old);
 425       if (G1ConcRegionFreeingVerbose) {
 426         gclog_or_tty->print_cr("G1ConcRegionFreeing [region alloc] : "
 427                                "allocated " HR_FORMAT " from secondary_free_list",
 428                                HR_FORMAT_PARAMS(res));
 429       }
 430       return res;
 431     }
 432 
 433     // Wait here until we get notified either when (a) there are no
 434     // more free regions coming or (b) some regions have been moved on
 435     // the secondary_free_list.
 436     SecondaryFreeList_lock->wait(Mutex::_no_safepoint_check_flag);
 437   }
 438 
 439   if (G1ConcRegionFreeingVerbose) {
 440     gclog_or_tty->print_cr("G1ConcRegionFreeing [region alloc] : "
 441                            "could not allocate from secondary_free_list");
 442   }
 443   return NULL;
 444 }
 445 
 446 HeapRegion* G1CollectedHeap::new_region(size_t word_size, bool is_old, bool do_expand) {
 447   assert(!is_humongous(word_size) || word_size <= HeapRegion::GrainWords,
 448          "the only time we use this to allocate a humongous region is "
 449          "when we are allocating a single humongous region");
 450 
 451   HeapRegion* res;
 452   if (G1StressConcRegionFreeing) {
 453     if (!_secondary_free_list.is_empty()) {
 454       if (G1ConcRegionFreeingVerbose) {
 455         gclog_or_tty->print_cr("G1ConcRegionFreeing [region alloc] : "
 456                                "forced to look at the secondary_free_list");
 457       }
 458       res = new_region_try_secondary_free_list(is_old);
 459       if (res != NULL) {
 460         return res;
 461       }
 462     }
 463   }
 464 
 465   res = _hrm.allocate_free_region(is_old);
 466 
 467   if (res == NULL) {
 468     if (G1ConcRegionFreeingVerbose) {
 469       gclog_or_tty->print_cr("G1ConcRegionFreeing [region alloc] : "
 470                              "res == NULL, trying the secondary_free_list");
 471     }
 472     res = new_region_try_secondary_free_list(is_old);
 473   }
 474   if (res == NULL && do_expand && _expand_heap_after_alloc_failure) {
 475     // Currently, only attempts to allocate GC alloc regions set
 476     // do_expand to true. So, we should only reach here during a
 477     // safepoint. If this assumption changes we might have to
 478     // reconsider the use of _expand_heap_after_alloc_failure.
 479     assert(SafepointSynchronize::is_at_safepoint(), "invariant");
 480 
 481     ergo_verbose1(ErgoHeapSizing,
 482                   "attempt heap expansion",
 483                   ergo_format_reason("region allocation request failed")
 484                   ergo_format_byte("allocation request"),
 485                   word_size * HeapWordSize);
 486     if (expand(word_size * HeapWordSize)) {
 487       // Given that expand() succeeded in expanding the heap, and we
 488       // always expand the heap by an amount aligned to the heap
 489       // region size, the free list should in theory not be empty.
 490       // In either case allocate_free_region() will check for NULL.
 491       res = _hrm.allocate_free_region(is_old);
 492     } else {
 493       _expand_heap_after_alloc_failure = false;
 494     }
 495   }
 496   return res;
 497 }
 498 
 499 HeapWord*
 500 G1CollectedHeap::humongous_obj_allocate_initialize_regions(uint first,
 501                                                            uint num_regions,
 502                                                            size_t word_size,
 503                                                            AllocationContext_t context) {
 504   assert(first != G1_NO_HRM_INDEX, "pre-condition");
 505   assert(is_humongous(word_size), "word_size should be humongous");
 506   assert(num_regions * HeapRegion::GrainWords >= word_size, "pre-condition");
 507 
 508   // Index of last region in the series + 1.
 509   uint last = first + num_regions;
 510 
 511   // We need to initialize the region(s) we just discovered. This is
 512   // a bit tricky given that it can happen concurrently with
 513   // refinement threads refining cards on these regions and
 514   // potentially wanting to refine the BOT as they are scanning
 515   // those cards (this can happen shortly after a cleanup; see CR
 516   // 6991377). So we have to set up the region(s) carefully and in
 517   // a specific order.
 518 
 519   // The word size sum of all the regions we will allocate.
 520   size_t word_size_sum = (size_t) num_regions * HeapRegion::GrainWords;
 521   assert(word_size <= word_size_sum, "sanity");
 522 
 523   // This will be the "starts humongous" region.
 524   HeapRegion* first_hr = region_at(first);
 525   // The header of the new object will be placed at the bottom of
 526   // the first region.
 527   HeapWord* new_obj = first_hr->bottom();
 528   // This will be the new end of the first region in the series that
 529   // should also match the end of the last region in the series.
 530   HeapWord* new_end = new_obj + word_size_sum;
 531   // This will be the new top of the first region that will reflect
 532   // this allocation.
 533   HeapWord* new_top = new_obj + word_size;
 534 
 535   // First, we need to zero the header of the space that we will be
 536   // allocating. When we update top further down, some refinement
 537   // threads might try to scan the region. By zeroing the header we
 538   // ensure that any thread that will try to scan the region will
 539   // come across the zero klass word and bail out.
 540   //
 541   // NOTE: It would not have been correct to have used
 542   // CollectedHeap::fill_with_object() and make the space look like
 543   // an int array. The thread that is doing the allocation will
 544   // later update the object header to a potentially different array
 545   // type and, for a very short period of time, the klass and length
 546   // fields will be inconsistent. This could cause a refinement
 547   // thread to calculate the object size incorrectly.
 548   Copy::fill_to_words(new_obj, oopDesc::header_size(), 0);
 549 
 550   // We will set up the first region as "starts humongous". This
 551   // will also update the BOT covering all the regions to reflect
 552   // that there is a single object that starts at the bottom of the
 553   // first region.
 554   first_hr->set_starts_humongous(new_top, new_end);
 555   first_hr->set_allocation_context(context);
 556   // Then, if there are any, we will set up the "continues
 557   // humongous" regions.
 558   HeapRegion* hr = NULL;
 559   for (uint i = first + 1; i < last; ++i) {
 560     hr = region_at(i);
 561     hr->set_continues_humongous(first_hr);
 562     hr->set_allocation_context(context);
 563   }
 564   // If we have "continues humongous" regions (hr != NULL), then the
 565   // end of the last one should match new_end.
 566   assert(hr == NULL || hr->end() == new_end, "sanity");
 567 
 568   // Up to this point no concurrent thread would have been able to
 569   // do any scanning on any region in this series. All the top
 570   // fields still point to bottom, so the intersection between
 571   // [bottom,top] and [card_start,card_end] will be empty. Before we
 572   // update the top fields, we'll do a storestore to make sure that
 573   // no thread sees the update to top before the zeroing of the
 574   // object header and the BOT initialization.
 575   OrderAccess::storestore();
 576 
 577   // Now that the BOT and the object header have been initialized,
 578   // we can update top of the "starts humongous" region.
 579   assert(first_hr->bottom() < new_top && new_top <= first_hr->end(),
 580          "new_top should be in this region");
 581   first_hr->set_top(new_top);
 582   if (_hr_printer.is_active()) {
 583     HeapWord* bottom = first_hr->bottom();
 584     HeapWord* end = first_hr->orig_end();
 585     if ((first + 1) == last) {
 586       // the series has a single humongous region
 587       _hr_printer.alloc(G1HRPrinter::SingleHumongous, first_hr, new_top);
 588     } else {
 589       // the series has more than one humongous regions
 590       _hr_printer.alloc(G1HRPrinter::StartsHumongous, first_hr, end);
 591     }
 592   }
 593 
 594   // Now, we will update the top fields of the "continues humongous"
 595   // regions. The reason we need to do this is that, otherwise,
 596   // these regions would look empty and this will confuse parts of
 597   // G1. For example, the code that looks for a consecutive number
 598   // of empty regions will consider them empty and try to
 599   // re-allocate them. We can extend is_empty() to also include
 600   // !is_continues_humongous(), but it is easier to just update the top
 601   // fields here. The way we set top for all regions (i.e., top ==
 602   // end for all regions but the last one, top == new_top for the
 603   // last one) is actually used when we will free up the humongous
 604   // region in free_humongous_region().
 605   hr = NULL;
 606   for (uint i = first + 1; i < last; ++i) {
 607     hr = region_at(i);
 608     if ((i + 1) == last) {
 609       // last continues humongous region
 610       assert(hr->bottom() < new_top && new_top <= hr->end(),
 611              "new_top should fall on this region");
 612       hr->set_top(new_top);
 613       _hr_printer.alloc(G1HRPrinter::ContinuesHumongous, hr, new_top);
 614     } else {
 615       // not last one
 616       assert(new_top > hr->end(), "new_top should be above this region");
 617       hr->set_top(hr->end());
 618       _hr_printer.alloc(G1HRPrinter::ContinuesHumongous, hr, hr->end());
 619     }
 620   }
 621   // If we have continues humongous regions (hr != NULL), then the
 622   // end of the last one should match new_end and its top should
 623   // match new_top.
 624   assert(hr == NULL ||
 625          (hr->end() == new_end && hr->top() == new_top), "sanity");
 626   check_bitmaps("Humongous Region Allocation", first_hr);
 627 
 628   assert(first_hr->used() == word_size * HeapWordSize, "invariant");
 629   increase_used(first_hr->used());
 630   _humongous_set.add(first_hr);
 631 
 632   return new_obj;
 633 }
 634 
 635 // If could fit into free regions w/o expansion, try.
 636 // Otherwise, if can expand, do so.
 637 // Otherwise, if using ex regions might help, try with ex given back.
 638 HeapWord* G1CollectedHeap::humongous_obj_allocate(size_t word_size, AllocationContext_t context) {
 639   assert_heap_locked_or_at_safepoint(true /* should_be_vm_thread */);
 640 
 641   verify_region_sets_optional();
 642 
 643   uint first = G1_NO_HRM_INDEX;
 644   uint obj_regions = (uint)(align_size_up_(word_size, HeapRegion::GrainWords) / HeapRegion::GrainWords);
 645 
 646   if (obj_regions == 1) {
 647     // Only one region to allocate, try to use a fast path by directly allocating
 648     // from the free lists. Do not try to expand here, we will potentially do that
 649     // later.
 650     HeapRegion* hr = new_region(word_size, true /* is_old */, false /* do_expand */);
 651     if (hr != NULL) {
 652       first = hr->hrm_index();
 653     }
 654   } else {
 655     // We can't allocate humongous regions spanning more than one region while
 656     // cleanupComplete() is running, since some of the regions we find to be
 657     // empty might not yet be added to the free list. It is not straightforward
 658     // to know in which list they are on so that we can remove them. We only
 659     // need to do this if we need to allocate more than one region to satisfy the
 660     // current humongous allocation request. If we are only allocating one region
 661     // we use the one-region region allocation code (see above), that already
 662     // potentially waits for regions from the secondary free list.
 663     wait_while_free_regions_coming();
 664     append_secondary_free_list_if_not_empty_with_lock();
 665 
 666     // Policy: Try only empty regions (i.e. already committed first). Maybe we
 667     // are lucky enough to find some.
 668     first = _hrm.find_contiguous_only_empty(obj_regions);
 669     if (first != G1_NO_HRM_INDEX) {
 670       _hrm.allocate_free_regions_starting_at(first, obj_regions);
 671     }
 672   }
 673 
 674   if (first == G1_NO_HRM_INDEX) {
 675     // Policy: We could not find enough regions for the humongous object in the
 676     // free list. Look through the heap to find a mix of free and uncommitted regions.
 677     // If so, try expansion.
 678     first = _hrm.find_contiguous_empty_or_unavailable(obj_regions);
 679     if (first != G1_NO_HRM_INDEX) {
 680       // We found something. Make sure these regions are committed, i.e. expand
 681       // the heap. Alternatively we could do a defragmentation GC.
 682       ergo_verbose1(ErgoHeapSizing,
 683                     "attempt heap expansion",
 684                     ergo_format_reason("humongous allocation request failed")
 685                     ergo_format_byte("allocation request"),
 686                     word_size * HeapWordSize);
 687 
 688       _hrm.expand_at(first, obj_regions);
 689       g1_policy()->record_new_heap_size(num_regions());
 690 
 691 #ifdef ASSERT
 692       for (uint i = first; i < first + obj_regions; ++i) {
 693         HeapRegion* hr = region_at(i);
 694         assert(hr->is_free(), "sanity");
 695         assert(hr->is_empty(), "sanity");
 696         assert(is_on_master_free_list(hr), "sanity");
 697       }
 698 #endif
 699       _hrm.allocate_free_regions_starting_at(first, obj_regions);
 700     } else {
 701       // Policy: Potentially trigger a defragmentation GC.
 702     }
 703   }
 704 
 705   HeapWord* result = NULL;
 706   if (first != G1_NO_HRM_INDEX) {
 707     result = humongous_obj_allocate_initialize_regions(first, obj_regions,
 708                                                        word_size, context);
 709     assert(result != NULL, "it should always return a valid result");
 710 
 711     // A successful humongous object allocation changes the used space
 712     // information of the old generation so we need to recalculate the
 713     // sizes and update the jstat counters here.
 714     g1mm()->update_sizes();
 715   }
 716 
 717   verify_region_sets_optional();
 718 
 719   return result;
 720 }
 721 
 722 HeapWord* G1CollectedHeap::allocate_new_tlab(size_t word_size) {
 723   assert_heap_not_locked_and_not_at_safepoint();
 724   assert(!is_humongous(word_size), "we do not allow humongous TLABs");
 725 
 726   uint dummy_gc_count_before;
 727   uint dummy_gclocker_retry_count = 0;
 728   return attempt_allocation(word_size, &dummy_gc_count_before, &dummy_gclocker_retry_count);
 729 }
 730 
 731 HeapWord*
 732 G1CollectedHeap::mem_allocate(size_t word_size,
 733                               bool*  gc_overhead_limit_was_exceeded) {
 734   assert_heap_not_locked_and_not_at_safepoint();
 735 
 736   // Loop until the allocation is satisfied, or unsatisfied after GC.
 737   for (uint try_count = 1, gclocker_retry_count = 0; /* we'll return */; try_count += 1) {
 738     uint gc_count_before;
 739 
 740     HeapWord* result = NULL;
 741     if (!is_humongous(word_size)) {
 742       result = attempt_allocation(word_size, &gc_count_before, &gclocker_retry_count);
 743     } else {
 744       result = attempt_allocation_humongous(word_size, &gc_count_before, &gclocker_retry_count);
 745     }
 746     if (result != NULL) {
 747       return result;
 748     }
 749 
 750     // Create the garbage collection operation...
 751     VM_G1CollectForAllocation op(gc_count_before, word_size);
 752     op.set_allocation_context(AllocationContext::current());
 753 
 754     // ...and get the VM thread to execute it.
 755     VMThread::execute(&op);
 756 
 757     if (op.prologue_succeeded() && op.pause_succeeded()) {
 758       // If the operation was successful we'll return the result even
 759       // if it is NULL. If the allocation attempt failed immediately
 760       // after a Full GC, it's unlikely we'll be able to allocate now.
 761       HeapWord* result = op.result();
 762       if (result != NULL && !is_humongous(word_size)) {
 763         // Allocations that take place on VM operations do not do any
 764         // card dirtying and we have to do it here. We only have to do
 765         // this for non-humongous allocations, though.
 766         dirty_young_block(result, word_size);
 767       }
 768       return result;
 769     } else {
 770       if (gclocker_retry_count > GCLockerRetryAllocationCount) {
 771         return NULL;
 772       }
 773       assert(op.result() == NULL,
 774              "the result should be NULL if the VM op did not succeed");
 775     }
 776 
 777     // Give a warning if we seem to be looping forever.
 778     if ((QueuedAllocationWarningCount > 0) &&
 779         (try_count % QueuedAllocationWarningCount == 0)) {
 780       warning("G1CollectedHeap::mem_allocate retries %d times", try_count);
 781     }
 782   }
 783 
 784   ShouldNotReachHere();
 785   return NULL;
 786 }
 787 
 788 HeapWord* G1CollectedHeap::attempt_allocation_slow(size_t word_size,
 789                                                    AllocationContext_t context,
 790                                                    uint* gc_count_before_ret,
 791                                                    uint* gclocker_retry_count_ret) {
 792   // Make sure you read the note in attempt_allocation_humongous().
 793 
 794   assert_heap_not_locked_and_not_at_safepoint();
 795   assert(!is_humongous(word_size), "attempt_allocation_slow() should not "
 796          "be called for humongous allocation requests");
 797 
 798   // We should only get here after the first-level allocation attempt
 799   // (attempt_allocation()) failed to allocate.
 800 
 801   // We will loop until a) we manage to successfully perform the
 802   // allocation or b) we successfully schedule a collection which
 803   // fails to perform the allocation. b) is the only case when we'll
 804   // return NULL.
 805   HeapWord* result = NULL;
 806   for (int try_count = 1; /* we'll return */; try_count += 1) {
 807     bool should_try_gc;
 808     uint gc_count_before;
 809 
 810     {
 811       MutexLockerEx x(Heap_lock);
 812       result = _allocator->attempt_allocation_locked(word_size, context);
 813       if (result != NULL) {
 814         return result;
 815       }
 816 
 817       if (GC_locker::is_active_and_needs_gc()) {
 818         if (g1_policy()->can_expand_young_list()) {
 819           // No need for an ergo verbose message here,
 820           // can_expand_young_list() does this when it returns true.
 821           result = _allocator->attempt_allocation_force(word_size, context);
 822           if (result != NULL) {
 823             return result;
 824           }
 825         }
 826         should_try_gc = false;
 827       } else {
 828         // The GCLocker may not be active but the GCLocker initiated
 829         // GC may not yet have been performed (GCLocker::needs_gc()
 830         // returns true). In this case we do not try this GC and
 831         // wait until the GCLocker initiated GC is performed, and
 832         // then retry the allocation.
 833         if (GC_locker::needs_gc()) {
 834           should_try_gc = false;
 835         } else {
 836           // Read the GC count while still holding the Heap_lock.
 837           gc_count_before = total_collections();
 838           should_try_gc = true;
 839         }
 840       }
 841     }
 842 
 843     if (should_try_gc) {
 844       bool succeeded;
 845       result = do_collection_pause(word_size, gc_count_before, &succeeded,
 846                                    GCCause::_g1_inc_collection_pause);
 847       if (result != NULL) {
 848         assert(succeeded, "only way to get back a non-NULL result");
 849         return result;
 850       }
 851 
 852       if (succeeded) {
 853         // If we get here we successfully scheduled a collection which
 854         // failed to allocate. No point in trying to allocate
 855         // further. We'll just return NULL.
 856         MutexLockerEx x(Heap_lock);
 857         *gc_count_before_ret = total_collections();
 858         return NULL;
 859       }
 860     } else {
 861       if (*gclocker_retry_count_ret > GCLockerRetryAllocationCount) {
 862         MutexLockerEx x(Heap_lock);
 863         *gc_count_before_ret = total_collections();
 864         return NULL;
 865       }
 866       // The GCLocker is either active or the GCLocker initiated
 867       // GC has not yet been performed. Stall until it is and
 868       // then retry the allocation.
 869       GC_locker::stall_until_clear();
 870       (*gclocker_retry_count_ret) += 1;
 871     }
 872 
 873     // We can reach here if we were unsuccessful in scheduling a
 874     // collection (because another thread beat us to it) or if we were
 875     // stalled due to the GC locker. In either can we should retry the
 876     // allocation attempt in case another thread successfully
 877     // performed a collection and reclaimed enough space. We do the
 878     // first attempt (without holding the Heap_lock) here and the
 879     // follow-on attempt will be at the start of the next loop
 880     // iteration (after taking the Heap_lock).
 881     result = _allocator->attempt_allocation(word_size, context);
 882     if (result != NULL) {
 883       return result;
 884     }
 885 
 886     // Give a warning if we seem to be looping forever.
 887     if ((QueuedAllocationWarningCount > 0) &&
 888         (try_count % QueuedAllocationWarningCount == 0)) {
 889       warning("G1CollectedHeap::attempt_allocation_slow() "
 890               "retries %d times", try_count);
 891     }
 892   }
 893 
 894   ShouldNotReachHere();
 895   return NULL;
 896 }
 897 
 898 void G1CollectedHeap::begin_archive_alloc_range() {
 899   assert_at_safepoint(true /* should_be_vm_thread */);
 900   if (_archive_allocator == NULL) {
 901     _archive_allocator = G1ArchiveAllocator::create_allocator(this);
 902   }
 903 }
 904 
 905 bool G1CollectedHeap::is_archive_alloc_too_large(size_t word_size) {
 906   // Allocations in archive regions cannot be of a size that would be considered
 907   // humongous even for a minimum-sized region, because G1 region sizes/boundaries
 908   // may be different at archive-restore time.
 909   return word_size >= humongous_threshold_for(HeapRegion::min_region_size_in_words());
 910 }
 911 
 912 HeapWord* G1CollectedHeap::archive_mem_allocate(size_t word_size) {
 913   assert_at_safepoint(true /* should_be_vm_thread */);
 914   assert(_archive_allocator != NULL, "_archive_allocator not initialized");
 915   if (is_archive_alloc_too_large(word_size)) {
 916     return NULL;
 917   }
 918   return _archive_allocator->archive_mem_allocate(word_size);
 919 }
 920 
 921 void G1CollectedHeap::end_archive_alloc_range(GrowableArray<MemRegion>* ranges,
 922                                               size_t end_alignment_in_bytes) {
 923   assert_at_safepoint(true /* should_be_vm_thread */);
 924   assert(_archive_allocator != NULL, "_archive_allocator not initialized");
 925 
 926   // Call complete_archive to do the real work, filling in the MemRegion
 927   // array with the archive regions.
 928   _archive_allocator->complete_archive(ranges, end_alignment_in_bytes);
 929   delete _archive_allocator;
 930   _archive_allocator = NULL;
 931 }
 932 
 933 bool G1CollectedHeap::check_archive_addresses(MemRegion* ranges, size_t count) {
 934   assert(ranges != NULL, "MemRegion array NULL");
 935   assert(count != 0, "No MemRegions provided");
 936   MemRegion reserved = _hrm.reserved();
 937   for (size_t i = 0; i < count; i++) {
 938     if (!reserved.contains(ranges[i].start()) || !reserved.contains(ranges[i].last())) {
 939       return false;
 940     }
 941   }
 942   return true;
 943 }
 944 
 945 bool G1CollectedHeap::alloc_archive_regions(MemRegion* ranges, size_t count) {
 946   assert(!is_init_completed(), "Expect to be called at JVM init time");
 947   assert(ranges != NULL, "MemRegion array NULL");
 948   assert(count != 0, "No MemRegions provided");
 949   MutexLockerEx x(Heap_lock);
 950 
 951   MemRegion reserved = _hrm.reserved();
 952   HeapWord* prev_last_addr = NULL;
 953   HeapRegion* prev_last_region = NULL;
 954 
 955   // Temporarily disable pretouching of heap pages. This interface is used
 956   // when mmap'ing archived heap data in, so pre-touching is wasted.
 957   FlagSetting fs(AlwaysPreTouch, false);
 958 
 959   // Enable archive object checking in G1MarkSweep. We have to let it know
 960   // about each archive range, so that objects in those ranges aren't marked.
 961   G1MarkSweep::enable_archive_object_check();
 962 
 963   // For each specified MemRegion range, allocate the corresponding G1
 964   // regions and mark them as archive regions. We expect the ranges in
 965   // ascending starting address order, without overlap.
 966   for (size_t i = 0; i < count; i++) {
 967     MemRegion curr_range = ranges[i];
 968     HeapWord* start_address = curr_range.start();
 969     size_t word_size = curr_range.word_size();
 970     HeapWord* last_address = curr_range.last();
 971     size_t commits = 0;
 972 
 973     guarantee(reserved.contains(start_address) && reserved.contains(last_address),
 974               err_msg("MemRegion outside of heap [" PTR_FORMAT ", " PTR_FORMAT "]",
 975               p2i(start_address), p2i(last_address)));
 976     guarantee(start_address > prev_last_addr,
 977               err_msg("Ranges not in ascending order: " PTR_FORMAT " <= " PTR_FORMAT ,
 978               p2i(start_address), p2i(prev_last_addr)));
 979     prev_last_addr = last_address;
 980 
 981     // Check for ranges that start in the same G1 region in which the previous
 982     // range ended, and adjust the start address so we don't try to allocate
 983     // the same region again. If the current range is entirely within that
 984     // region, skip it, just adjusting the recorded top.
 985     HeapRegion* start_region = _hrm.addr_to_region(start_address);
 986     if ((prev_last_region != NULL) && (start_region == prev_last_region)) {
 987       start_address = start_region->end();
 988       if (start_address > last_address) {
 989         increase_used(word_size * HeapWordSize);
 990         start_region->set_top(last_address + 1);
 991         continue;
 992       }
 993       start_region->set_top(start_address);
 994       curr_range = MemRegion(start_address, last_address + 1);
 995       start_region = _hrm.addr_to_region(start_address);
 996     }
 997 
 998     // Perform the actual region allocation, exiting if it fails.
 999     // Then note how much new space we have allocated.
1000     if (!_hrm.allocate_containing_regions(curr_range, &commits)) {
1001       return false;
1002     }
1003     increase_used(word_size * HeapWordSize);
1004     if (commits != 0) {
1005       ergo_verbose1(ErgoHeapSizing,
1006                     "attempt heap expansion",
1007                     ergo_format_reason("allocate archive regions")
1008                     ergo_format_byte("total size"),
1009                     HeapRegion::GrainWords * HeapWordSize * commits);
1010     }
1011 
1012     // Mark each G1 region touched by the range as archive, add it to the old set,
1013     // and set the allocation context and top.
1014     HeapRegion* curr_region = _hrm.addr_to_region(start_address);
1015     HeapRegion* last_region = _hrm.addr_to_region(last_address);
1016     prev_last_region = last_region;
1017 
1018     while (curr_region != NULL) {
1019       assert(curr_region->is_empty() && !curr_region->is_pinned(),
1020              err_msg("Region already in use (index %u)", curr_region->hrm_index()));
1021       _hr_printer.alloc(curr_region, G1HRPrinter::Archive);
1022       curr_region->set_allocation_context(AllocationContext::system());
1023       curr_region->set_archive();
1024       _old_set.add(curr_region);
1025       if (curr_region != last_region) {
1026         curr_region->set_top(curr_region->end());
1027         curr_region = _hrm.next_region_in_heap(curr_region);
1028       } else {
1029         curr_region->set_top(last_address + 1);
1030         curr_region = NULL;
1031       }
1032     }
1033 
1034     // Notify mark-sweep of the archive range.
1035     G1MarkSweep::set_range_archive(curr_range, true);
1036   }
1037   return true;
1038 }
1039 
1040 void G1CollectedHeap::fill_archive_regions(MemRegion* ranges, size_t count) {
1041   assert(!is_init_completed(), "Expect to be called at JVM init time");
1042   assert(ranges != NULL, "MemRegion array NULL");
1043   assert(count != 0, "No MemRegions provided");
1044   MemRegion reserved = _hrm.reserved();
1045   HeapWord *prev_last_addr = NULL;
1046   HeapRegion* prev_last_region = NULL;
1047 
1048   // For each MemRegion, create filler objects, if needed, in the G1 regions
1049   // that contain the address range. The address range actually within the
1050   // MemRegion will not be modified. That is assumed to have been initialized
1051   // elsewhere, probably via an mmap of archived heap data.
1052   MutexLockerEx x(Heap_lock);
1053   for (size_t i = 0; i < count; i++) {
1054     HeapWord* start_address = ranges[i].start();
1055     HeapWord* last_address = ranges[i].last();
1056 
1057     assert(reserved.contains(start_address) && reserved.contains(last_address),
1058            err_msg("MemRegion outside of heap [" PTR_FORMAT ", " PTR_FORMAT "]",
1059                    p2i(start_address), p2i(last_address)));
1060     assert(start_address > prev_last_addr,
1061            err_msg("Ranges not in ascending order: " PTR_FORMAT " <= " PTR_FORMAT ,
1062                    p2i(start_address), p2i(prev_last_addr)));
1063 
1064     HeapRegion* start_region = _hrm.addr_to_region(start_address);
1065     HeapRegion* last_region = _hrm.addr_to_region(last_address);
1066     HeapWord* bottom_address = start_region->bottom();
1067 
1068     // Check for a range beginning in the same region in which the
1069     // previous one ended.
1070     if (start_region == prev_last_region) {
1071       bottom_address = prev_last_addr + 1;
1072     }
1073 
1074     // Verify that the regions were all marked as archive regions by
1075     // alloc_archive_regions.
1076     HeapRegion* curr_region = start_region;
1077     while (curr_region != NULL) {
1078       guarantee(curr_region->is_archive(),
1079                 err_msg("Expected archive region at index %u", curr_region->hrm_index()));
1080       if (curr_region != last_region) {
1081         curr_region = _hrm.next_region_in_heap(curr_region);
1082       } else {
1083         curr_region = NULL;
1084       }
1085     }
1086 
1087     prev_last_addr = last_address;
1088     prev_last_region = last_region;
1089 
1090     // Fill the memory below the allocated range with dummy object(s),
1091     // if the region bottom does not match the range start, or if the previous
1092     // range ended within the same G1 region, and there is a gap.
1093     if (start_address != bottom_address) {
1094       size_t fill_size = pointer_delta(start_address, bottom_address);
1095       G1CollectedHeap::fill_with_objects(bottom_address, fill_size);
1096       increase_used(fill_size * HeapWordSize);
1097     }
1098   }
1099 }
1100 
1101 inline HeapWord* G1CollectedHeap::attempt_allocation(size_t word_size,
1102                                                      uint* gc_count_before_ret,
1103                                                      uint* gclocker_retry_count_ret) {
1104   assert_heap_not_locked_and_not_at_safepoint();
1105   assert(!is_humongous(word_size), "attempt_allocation() should not "
1106          "be called for humongous allocation requests");
1107 
1108   AllocationContext_t context = AllocationContext::current();
1109   HeapWord* result = _allocator->attempt_allocation(word_size, context);
1110 
1111   if (result == NULL) {
1112     result = attempt_allocation_slow(word_size,
1113                                      context,
1114                                      gc_count_before_ret,
1115                                      gclocker_retry_count_ret);
1116   }
1117   assert_heap_not_locked();
1118   if (result != NULL) {
1119     dirty_young_block(result, word_size);
1120   }
1121   return result;
1122 }
1123 
1124 void G1CollectedHeap::dealloc_archive_regions(MemRegion* ranges, size_t count) {
1125   assert(!is_init_completed(), "Expect to be called at JVM init time");
1126   assert(ranges != NULL, "MemRegion array NULL");
1127   assert(count != 0, "No MemRegions provided");
1128   MemRegion reserved = _hrm.reserved();
1129   HeapWord* prev_last_addr = NULL;
1130   HeapRegion* prev_last_region = NULL;
1131   size_t size_used = 0;
1132   size_t uncommitted_regions = 0;
1133 
1134   // For each Memregion, free the G1 regions that constitute it, and
1135   // notify mark-sweep that the range is no longer to be considered 'archive.'
1136   MutexLockerEx x(Heap_lock);
1137   for (size_t i = 0; i < count; i++) {
1138     HeapWord* start_address = ranges[i].start();
1139     HeapWord* last_address = ranges[i].last();
1140 
1141     assert(reserved.contains(start_address) && reserved.contains(last_address),
1142            err_msg("MemRegion outside of heap [" PTR_FORMAT ", " PTR_FORMAT "]",
1143                    p2i(start_address), p2i(last_address)));
1144     assert(start_address > prev_last_addr,
1145            err_msg("Ranges not in ascending order: " PTR_FORMAT " <= " PTR_FORMAT ,
1146                    p2i(start_address), p2i(prev_last_addr)));
1147     size_used += ranges[i].byte_size();
1148     prev_last_addr = last_address;
1149 
1150     HeapRegion* start_region = _hrm.addr_to_region(start_address);
1151     HeapRegion* last_region = _hrm.addr_to_region(last_address);
1152 
1153     // Check for ranges that start in the same G1 region in which the previous
1154     // range ended, and adjust the start address so we don't try to free
1155     // the same region again. If the current range is entirely within that
1156     // region, skip it.
1157     if (start_region == prev_last_region) {
1158       start_address = start_region->end();
1159       if (start_address > last_address) {
1160         continue;
1161       }
1162       start_region = _hrm.addr_to_region(start_address);
1163     }
1164     prev_last_region = last_region;
1165 
1166     // After verifying that each region was marked as an archive region by
1167     // alloc_archive_regions, set it free and empty and uncommit it.
1168     HeapRegion* curr_region = start_region;
1169     while (curr_region != NULL) {
1170       guarantee(curr_region->is_archive(),
1171                 err_msg("Expected archive region at index %u", curr_region->hrm_index()));
1172       uint curr_index = curr_region->hrm_index();
1173       _old_set.remove(curr_region);
1174       curr_region->set_free();
1175       curr_region->set_top(curr_region->bottom());
1176       if (curr_region != last_region) {
1177         curr_region = _hrm.next_region_in_heap(curr_region);
1178       } else {
1179         curr_region = NULL;
1180       }
1181       _hrm.shrink_at(curr_index, 1);
1182       uncommitted_regions++;
1183     }
1184 
1185     // Notify mark-sweep that this is no longer an archive range.
1186     G1MarkSweep::set_range_archive(ranges[i], false);
1187   }
1188 
1189   if (uncommitted_regions != 0) {
1190     ergo_verbose1(ErgoHeapSizing,
1191                   "attempt heap shrinking",
1192                   ergo_format_reason("uncommitted archive regions")
1193                   ergo_format_byte("total size"),
1194                   HeapRegion::GrainWords * HeapWordSize * uncommitted_regions);
1195   }
1196   decrease_used(size_used);
1197 }
1198 
1199 HeapWord* G1CollectedHeap::attempt_allocation_humongous(size_t word_size,
1200                                                         uint* gc_count_before_ret,
1201                                                         uint* gclocker_retry_count_ret) {
1202   // The structure of this method has a lot of similarities to
1203   // attempt_allocation_slow(). The reason these two were not merged
1204   // into a single one is that such a method would require several "if
1205   // allocation is not humongous do this, otherwise do that"
1206   // conditional paths which would obscure its flow. In fact, an early
1207   // version of this code did use a unified method which was harder to
1208   // follow and, as a result, it had subtle bugs that were hard to
1209   // track down. So keeping these two methods separate allows each to
1210   // be more readable. It will be good to keep these two in sync as
1211   // much as possible.
1212 
1213   assert_heap_not_locked_and_not_at_safepoint();
1214   assert(is_humongous(word_size), "attempt_allocation_humongous() "
1215          "should only be called for humongous allocations");
1216 
1217   // Humongous objects can exhaust the heap quickly, so we should check if we
1218   // need to start a marking cycle at each humongous object allocation. We do
1219   // the check before we do the actual allocation. The reason for doing it
1220   // before the allocation is that we avoid having to keep track of the newly
1221   // allocated memory while we do a GC.
1222   if (g1_policy()->need_to_start_conc_mark("concurrent humongous allocation",
1223                                            word_size)) {
1224     collect(GCCause::_g1_humongous_allocation);
1225   }
1226 
1227   // We will loop until a) we manage to successfully perform the
1228   // allocation or b) we successfully schedule a collection which
1229   // fails to perform the allocation. b) is the only case when we'll
1230   // return NULL.
1231   HeapWord* result = NULL;
1232   for (int try_count = 1; /* we'll return */; try_count += 1) {
1233     bool should_try_gc;
1234     uint gc_count_before;
1235 
1236     {
1237       MutexLockerEx x(Heap_lock);
1238 
1239       // Given that humongous objects are not allocated in young
1240       // regions, we'll first try to do the allocation without doing a
1241       // collection hoping that there's enough space in the heap.
1242       result = humongous_obj_allocate(word_size, AllocationContext::current());
1243       if (result != NULL) {
1244         return result;
1245       }
1246 
1247       if (GC_locker::is_active_and_needs_gc()) {
1248         should_try_gc = false;
1249       } else {
1250          // The GCLocker may not be active but the GCLocker initiated
1251         // GC may not yet have been performed (GCLocker::needs_gc()
1252         // returns true). In this case we do not try this GC and
1253         // wait until the GCLocker initiated GC is performed, and
1254         // then retry the allocation.
1255         if (GC_locker::needs_gc()) {
1256           should_try_gc = false;
1257         } else {
1258           // Read the GC count while still holding the Heap_lock.
1259           gc_count_before = total_collections();
1260           should_try_gc = true;
1261         }
1262       }
1263     }
1264 
1265     if (should_try_gc) {
1266       // If we failed to allocate the humongous object, we should try to
1267       // do a collection pause (if we're allowed) in case it reclaims
1268       // enough space for the allocation to succeed after the pause.
1269 
1270       bool succeeded;
1271       result = do_collection_pause(word_size, gc_count_before, &succeeded,
1272                                    GCCause::_g1_humongous_allocation);
1273       if (result != NULL) {
1274         assert(succeeded, "only way to get back a non-NULL result");
1275         return result;
1276       }
1277 
1278       if (succeeded) {
1279         // If we get here we successfully scheduled a collection which
1280         // failed to allocate. No point in trying to allocate
1281         // further. We'll just return NULL.
1282         MutexLockerEx x(Heap_lock);
1283         *gc_count_before_ret = total_collections();
1284         return NULL;
1285       }
1286     } else {
1287       if (*gclocker_retry_count_ret > GCLockerRetryAllocationCount) {
1288         MutexLockerEx x(Heap_lock);
1289         *gc_count_before_ret = total_collections();
1290         return NULL;
1291       }
1292       // The GCLocker is either active or the GCLocker initiated
1293       // GC has not yet been performed. Stall until it is and
1294       // then retry the allocation.
1295       GC_locker::stall_until_clear();
1296       (*gclocker_retry_count_ret) += 1;
1297     }
1298 
1299     // We can reach here if we were unsuccessful in scheduling a
1300     // collection (because another thread beat us to it) or if we were
1301     // stalled due to the GC locker. In either can we should retry the
1302     // allocation attempt in case another thread successfully
1303     // performed a collection and reclaimed enough space.  Give a
1304     // warning if we seem to be looping forever.
1305 
1306     if ((QueuedAllocationWarningCount > 0) &&
1307         (try_count % QueuedAllocationWarningCount == 0)) {
1308       warning("G1CollectedHeap::attempt_allocation_humongous() "
1309               "retries %d times", try_count);
1310     }
1311   }
1312 
1313   ShouldNotReachHere();
1314   return NULL;
1315 }
1316 
1317 HeapWord* G1CollectedHeap::attempt_allocation_at_safepoint(size_t word_size,
1318                                                            AllocationContext_t context,
1319                                                            bool expect_null_mutator_alloc_region) {
1320   assert_at_safepoint(true /* should_be_vm_thread */);
1321   assert(!_allocator->has_mutator_alloc_region(context) || !expect_null_mutator_alloc_region,
1322          "the current alloc region was unexpectedly found to be non-NULL");
1323 
1324   if (!is_humongous(word_size)) {
1325     return _allocator->attempt_allocation_locked(word_size, context);
1326   } else {
1327     HeapWord* result = humongous_obj_allocate(word_size, context);
1328     if (result != NULL && g1_policy()->need_to_start_conc_mark("STW humongous allocation")) {
1329       collector_state()->set_initiate_conc_mark_if_possible(true);
1330     }
1331     return result;
1332   }
1333 
1334   ShouldNotReachHere();
1335 }
1336 
1337 class PostMCRemSetClearClosure: public HeapRegionClosure {
1338   G1CollectedHeap* _g1h;
1339   ModRefBarrierSet* _mr_bs;
1340 public:
1341   PostMCRemSetClearClosure(G1CollectedHeap* g1h, ModRefBarrierSet* mr_bs) :
1342     _g1h(g1h), _mr_bs(mr_bs) {}
1343 
1344   bool doHeapRegion(HeapRegion* r) {
1345     HeapRegionRemSet* hrrs = r->rem_set();
1346 
1347     if (r->is_continues_humongous()) {
1348       // We'll assert that the strong code root list and RSet is empty
1349       assert(hrrs->strong_code_roots_list_length() == 0, "sanity");
1350       assert(hrrs->occupied() == 0, "RSet should be empty");
1351       return false;
1352     }
1353 
1354     _g1h->reset_gc_time_stamps(r);
1355     hrrs->clear();
1356     // You might think here that we could clear just the cards
1357     // corresponding to the used region.  But no: if we leave a dirty card
1358     // in a region we might allocate into, then it would prevent that card
1359     // from being enqueued, and cause it to be missed.
1360     // Re: the performance cost: we shouldn't be doing full GC anyway!
1361     _mr_bs->clear(MemRegion(r->bottom(), r->end()));
1362 
1363     return false;
1364   }
1365 };
1366 
1367 void G1CollectedHeap::clear_rsets_post_compaction() {
1368   PostMCRemSetClearClosure rs_clear(this, g1_barrier_set());
1369   heap_region_iterate(&rs_clear);
1370 }
1371 
1372 class RebuildRSOutOfRegionClosure: public HeapRegionClosure {
1373   G1CollectedHeap*   _g1h;
1374   UpdateRSOopClosure _cl;
1375 public:
1376   RebuildRSOutOfRegionClosure(G1CollectedHeap* g1, uint worker_i = 0) :
1377     _cl(g1->g1_rem_set(), worker_i),
1378     _g1h(g1)
1379   { }
1380 
1381   bool doHeapRegion(HeapRegion* r) {
1382     if (!r->is_continues_humongous()) {
1383       _cl.set_from(r);
1384       r->oop_iterate(&_cl);
1385     }
1386     return false;
1387   }
1388 };
1389 
1390 class ParRebuildRSTask: public AbstractGangTask {
1391   G1CollectedHeap* _g1;
1392   HeapRegionClaimer _hrclaimer;
1393 
1394 public:
1395   ParRebuildRSTask(G1CollectedHeap* g1) :
1396       AbstractGangTask("ParRebuildRSTask"), _g1(g1), _hrclaimer(g1->workers()->active_workers()) {}
1397 
1398   void work(uint worker_id) {
1399     RebuildRSOutOfRegionClosure rebuild_rs(_g1, worker_id);
1400     _g1->heap_region_par_iterate(&rebuild_rs, worker_id, &_hrclaimer);
1401   }
1402 };
1403 
1404 class PostCompactionPrinterClosure: public HeapRegionClosure {
1405 private:
1406   G1HRPrinter* _hr_printer;
1407 public:
1408   bool doHeapRegion(HeapRegion* hr) {
1409     assert(!hr->is_young(), "not expecting to find young regions");
1410     if (hr->is_free()) {
1411       // We only generate output for non-empty regions.
1412     } else if (hr->is_starts_humongous()) {
1413       if (hr->region_num() == 1) {
1414         // single humongous region
1415         _hr_printer->post_compaction(hr, G1HRPrinter::SingleHumongous);
1416       } else {
1417         _hr_printer->post_compaction(hr, G1HRPrinter::StartsHumongous);
1418       }
1419     } else if (hr->is_continues_humongous()) {
1420       _hr_printer->post_compaction(hr, G1HRPrinter::ContinuesHumongous);
1421     } else if (hr->is_archive()) {
1422       _hr_printer->post_compaction(hr, G1HRPrinter::Archive);
1423     } else if (hr->is_old()) {
1424       _hr_printer->post_compaction(hr, G1HRPrinter::Old);
1425     } else {
1426       ShouldNotReachHere();
1427     }
1428     return false;
1429   }
1430 
1431   PostCompactionPrinterClosure(G1HRPrinter* hr_printer)
1432     : _hr_printer(hr_printer) { }
1433 };
1434 
1435 void G1CollectedHeap::print_hrm_post_compaction() {
1436   PostCompactionPrinterClosure cl(hr_printer());
1437   heap_region_iterate(&cl);
1438 }
1439 
1440 bool G1CollectedHeap::do_collection(bool explicit_gc,
1441                                     bool clear_all_soft_refs,
1442                                     size_t word_size) {
1443   assert_at_safepoint(true /* should_be_vm_thread */);
1444 
1445   if (GC_locker::check_active_before_gc()) {
1446     return false;
1447   }
1448 
1449   STWGCTimer* gc_timer = G1MarkSweep::gc_timer();
1450   gc_timer->register_gc_start();
1451 
1452   SerialOldTracer* gc_tracer = G1MarkSweep::gc_tracer();
1453   gc_tracer->report_gc_start(gc_cause(), gc_timer->gc_start());
1454 
1455   SvcGCMarker sgcm(SvcGCMarker::FULL);
1456   ResourceMark rm;
1457 
1458   G1Log::update_level();
1459   print_heap_before_gc();
1460   trace_heap_before_gc(gc_tracer);
1461 
1462   size_t metadata_prev_used = MetaspaceAux::used_bytes();
1463 
1464   verify_region_sets_optional();
1465 
1466   const bool do_clear_all_soft_refs = clear_all_soft_refs ||
1467                            collector_policy()->should_clear_all_soft_refs();
1468 
1469   ClearedAllSoftRefs casr(do_clear_all_soft_refs, collector_policy());
1470 
1471   {
1472     IsGCActiveMark x;
1473 
1474     // Timing
1475     assert(!GCCause::is_user_requested_gc(gc_cause()) || explicit_gc, "invariant");
1476     TraceCPUTime tcpu(G1Log::finer(), true, gclog_or_tty);
1477 
1478     {
1479       GCTraceTime t(GCCauseString("Full GC", gc_cause()), G1Log::fine(), true, NULL, gc_tracer->gc_id());
1480       TraceCollectorStats tcs(g1mm()->full_collection_counters());
1481       TraceMemoryManagerStats tms(true /* fullGC */, gc_cause());
1482 
1483       g1_policy()->record_full_collection_start();
1484 
1485       // Note: When we have a more flexible GC logging framework that
1486       // allows us to add optional attributes to a GC log record we
1487       // could consider timing and reporting how long we wait in the
1488       // following two methods.
1489       wait_while_free_regions_coming();
1490       // If we start the compaction before the CM threads finish
1491       // scanning the root regions we might trip them over as we'll
1492       // be moving objects / updating references. So let's wait until
1493       // they are done. By telling them to abort, they should complete
1494       // early.
1495       _cm->root_regions()->abort();
1496       _cm->root_regions()->wait_until_scan_finished();
1497       append_secondary_free_list_if_not_empty_with_lock();
1498 
1499       gc_prologue(true);
1500       increment_total_collections(true /* full gc */);
1501       increment_old_marking_cycles_started();
1502 
1503       assert(used() == recalculate_used(), "Should be equal");
1504 
1505       verify_before_gc();
1506 
1507       check_bitmaps("Full GC Start");
1508       pre_full_gc_dump(gc_timer);
1509 
1510       COMPILER2_PRESENT(DerivedPointerTable::clear());


1511 
1512       // Disable discovery and empty the discovered lists
1513       // for the CM ref processor.
1514       ref_processor_cm()->disable_discovery();
1515       ref_processor_cm()->abandon_partial_discovery();
1516       ref_processor_cm()->verify_no_references_recorded();
1517 
1518       // Abandon current iterations of concurrent marking and concurrent
1519       // refinement, if any are in progress. We have to do this before
1520       // wait_until_scan_finished() below.
1521       concurrent_mark()->abort();
1522 
1523       // Make sure we'll choose a new allocation region afterwards.
1524       _allocator->release_mutator_alloc_region();
1525       _allocator->abandon_gc_alloc_regions();
1526       g1_rem_set()->cleanupHRRS();
1527 
1528       // We should call this after we retire any currently active alloc
1529       // regions so that all the ALLOC / RETIRE events are generated
1530       // before the start GC event.
1531       _hr_printer.start_gc(true /* full */, (size_t) total_collections());
1532 
1533       // We may have added regions to the current incremental collection
1534       // set between the last GC or pause and now. We need to clear the
1535       // incremental collection set and then start rebuilding it afresh
1536       // after this full GC.
1537       abandon_collection_set(g1_policy()->inc_cset_head());
1538       g1_policy()->clear_incremental_cset();
1539       g1_policy()->stop_incremental_cset_building();
1540 
1541       tear_down_region_sets(false /* free_list_only */);
1542       collector_state()->set_gcs_are_young(true);
1543 
1544       // See the comments in g1CollectedHeap.hpp and
1545       // G1CollectedHeap::ref_processing_init() about
1546       // how reference processing currently works in G1.
1547 
1548       // Temporarily make discovery by the STW ref processor single threaded (non-MT).
1549       ReferenceProcessorMTDiscoveryMutator stw_rp_disc_ser(ref_processor_stw(), false);
1550 
1551       // Temporarily clear the STW ref processor's _is_alive_non_header field.
1552       ReferenceProcessorIsAliveMutator stw_rp_is_alive_null(ref_processor_stw(), NULL);
1553 
1554       ref_processor_stw()->enable_discovery();
1555       ref_processor_stw()->setup_policy(do_clear_all_soft_refs);
1556 
1557       // Do collection work
1558       {
1559         HandleMark hm;  // Discard invalid handles created during gc
1560         G1MarkSweep::invoke_at_safepoint(ref_processor_stw(), do_clear_all_soft_refs);
1561       }
1562 
1563       assert(num_free_regions() == 0, "we should not have added any free regions");
1564       rebuild_region_sets(false /* free_list_only */);
1565 
1566       // Enqueue any discovered reference objects that have
1567       // not been removed from the discovered lists.
1568       ref_processor_stw()->enqueue_discovered_references();
1569 
1570       COMPILER2_PRESENT(DerivedPointerTable::update_pointers());


1571 
1572       MemoryService::track_memory_usage();
1573 
1574       assert(!ref_processor_stw()->discovery_enabled(), "Postcondition");
1575       ref_processor_stw()->verify_no_references_recorded();
1576 
1577       // Delete metaspaces for unloaded class loaders and clean up loader_data graph
1578       ClassLoaderDataGraph::purge();
1579       MetaspaceAux::verify_metrics();
1580 
1581       // Note: since we've just done a full GC, concurrent
1582       // marking is no longer active. Therefore we need not
1583       // re-enable reference discovery for the CM ref processor.
1584       // That will be done at the start of the next marking cycle.
1585       assert(!ref_processor_cm()->discovery_enabled(), "Postcondition");
1586       ref_processor_cm()->verify_no_references_recorded();
1587 
1588       reset_gc_time_stamp();
1589       // Since everything potentially moved, we will clear all remembered
1590       // sets, and clear all cards.  Later we will rebuild remembered
1591       // sets. We will also reset the GC time stamps of the regions.
1592       clear_rsets_post_compaction();
1593       check_gc_time_stamps();
1594 
1595       // Resize the heap if necessary.
1596       resize_if_necessary_after_full_collection(explicit_gc ? 0 : word_size);
1597 
1598       if (_hr_printer.is_active()) {
1599         // We should do this after we potentially resize the heap so
1600         // that all the COMMIT / UNCOMMIT events are generated before
1601         // the end GC event.
1602 
1603         print_hrm_post_compaction();
1604         _hr_printer.end_gc(true /* full */, (size_t) total_collections());
1605       }
1606 
1607       G1HotCardCache* hot_card_cache = _cg1r->hot_card_cache();
1608       if (hot_card_cache->use_cache()) {
1609         hot_card_cache->reset_card_counts();
1610         hot_card_cache->reset_hot_cache();
1611       }
1612 
1613       // Rebuild remembered sets of all regions.
1614       uint n_workers =
1615         AdaptiveSizePolicy::calc_active_workers(workers()->total_workers(),
1616                                                 workers()->active_workers(),
1617                                                 Threads::number_of_non_daemon_threads());
1618       workers()->set_active_workers(n_workers);
1619 
1620       ParRebuildRSTask rebuild_rs_task(this);
1621       workers()->run_task(&rebuild_rs_task);
1622 
1623       // Rebuild the strong code root lists for each region
1624       rebuild_strong_code_roots();
1625 
1626       if (true) { // FIXME
1627         MetaspaceGC::compute_new_size();
1628       }
1629 
1630 #ifdef TRACESPINNING
1631       ParallelTaskTerminator::print_termination_counts();
1632 #endif
1633 
1634       // Discard all rset updates
1635       JavaThread::dirty_card_queue_set().abandon_logs();
1636       assert(dirty_card_queue_set().completed_buffers_num() == 0, "DCQS should be empty");
1637 
1638       _young_list->reset_sampled_info();
1639       // At this point there should be no regions in the
1640       // entire heap tagged as young.
1641       assert(check_young_list_empty(true /* check_heap */),
1642              "young list should be empty at this point");
1643 
1644       // Update the number of full collections that have been completed.
1645       increment_old_marking_cycles_completed(false /* concurrent */);
1646 
1647       _hrm.verify_optional();
1648       verify_region_sets_optional();
1649 
1650       verify_after_gc();
1651 
1652       // Clear the previous marking bitmap, if needed for bitmap verification.
1653       // Note we cannot do this when we clear the next marking bitmap in
1654       // ConcurrentMark::abort() above since VerifyDuringGC verifies the
1655       // objects marked during a full GC against the previous bitmap.
1656       // But we need to clear it before calling check_bitmaps below since
1657       // the full GC has compacted objects and updated TAMS but not updated
1658       // the prev bitmap.
1659       if (G1VerifyBitmaps) {
1660         ((CMBitMap*) concurrent_mark()->prevMarkBitMap())->clearAll();
1661       }
1662       check_bitmaps("Full GC End");
1663 
1664       // Start a new incremental collection set for the next pause
1665       assert(g1_policy()->collection_set() == NULL, "must be");
1666       g1_policy()->start_incremental_cset_building();
1667 
1668       clear_cset_fast_test();
1669 
1670       _allocator->init_mutator_alloc_region();
1671 
1672       g1_policy()->record_full_collection_end();
1673 
1674       if (G1Log::fine()) {
1675         g1_policy()->print_heap_transition();
1676       }
1677 
1678       // We must call G1MonitoringSupport::update_sizes() in the same scoping level
1679       // as an active TraceMemoryManagerStats object (i.e. before the destructor for the
1680       // TraceMemoryManagerStats is called) so that the G1 memory pools are updated
1681       // before any GC notifications are raised.
1682       g1mm()->update_sizes();
1683 
1684       gc_epilogue(true);
1685     }
1686 
1687     if (G1Log::finer()) {
1688       g1_policy()->print_detailed_heap_transition(true /* full */);
1689     }
1690 
1691     print_heap_after_gc();
1692     trace_heap_after_gc(gc_tracer);
1693 
1694     post_full_gc_dump(gc_timer);
1695 
1696     gc_timer->register_gc_end();
1697     gc_tracer->report_gc_end(gc_timer->gc_end(), gc_timer->time_partitions());
1698   }
1699 
1700   return true;
1701 }
1702 
1703 void G1CollectedHeap::do_full_collection(bool clear_all_soft_refs) {
1704   // do_collection() will return whether it succeeded in performing
1705   // the GC. Currently, there is no facility on the
1706   // do_full_collection() API to notify the caller than the collection
1707   // did not succeed (e.g., because it was locked out by the GC
1708   // locker). So, right now, we'll ignore the return value.
1709   bool dummy = do_collection(true,                /* explicit_gc */
1710                              clear_all_soft_refs,
1711                              0                    /* word_size */);
1712 }
1713 
1714 // This code is mostly copied from TenuredGeneration.
1715 void
1716 G1CollectedHeap::
1717 resize_if_necessary_after_full_collection(size_t word_size) {
1718   // Include the current allocation, if any, and bytes that will be
1719   // pre-allocated to support collections, as "used".
1720   const size_t used_after_gc = used();
1721   const size_t capacity_after_gc = capacity();
1722   const size_t free_after_gc = capacity_after_gc - used_after_gc;
1723 
1724   // This is enforced in arguments.cpp.
1725   assert(MinHeapFreeRatio <= MaxHeapFreeRatio,
1726          "otherwise the code below doesn't make sense");
1727 
1728   // We don't have floating point command-line arguments
1729   const double minimum_free_percentage = (double) MinHeapFreeRatio / 100.0;
1730   const double maximum_used_percentage = 1.0 - minimum_free_percentage;
1731   const double maximum_free_percentage = (double) MaxHeapFreeRatio / 100.0;
1732   const double minimum_used_percentage = 1.0 - maximum_free_percentage;
1733 
1734   const size_t min_heap_size = collector_policy()->min_heap_byte_size();
1735   const size_t max_heap_size = collector_policy()->max_heap_byte_size();
1736 
1737   // We have to be careful here as these two calculations can overflow
1738   // 32-bit size_t's.
1739   double used_after_gc_d = (double) used_after_gc;
1740   double minimum_desired_capacity_d = used_after_gc_d / maximum_used_percentage;
1741   double maximum_desired_capacity_d = used_after_gc_d / minimum_used_percentage;
1742 
1743   // Let's make sure that they are both under the max heap size, which
1744   // by default will make them fit into a size_t.
1745   double desired_capacity_upper_bound = (double) max_heap_size;
1746   minimum_desired_capacity_d = MIN2(minimum_desired_capacity_d,
1747                                     desired_capacity_upper_bound);
1748   maximum_desired_capacity_d = MIN2(maximum_desired_capacity_d,
1749                                     desired_capacity_upper_bound);
1750 
1751   // We can now safely turn them into size_t's.
1752   size_t minimum_desired_capacity = (size_t) minimum_desired_capacity_d;
1753   size_t maximum_desired_capacity = (size_t) maximum_desired_capacity_d;
1754 
1755   // This assert only makes sense here, before we adjust them
1756   // with respect to the min and max heap size.
1757   assert(minimum_desired_capacity <= maximum_desired_capacity,
1758          err_msg("minimum_desired_capacity = " SIZE_FORMAT ", "
1759                  "maximum_desired_capacity = " SIZE_FORMAT,
1760                  minimum_desired_capacity, maximum_desired_capacity));
1761 
1762   // Should not be greater than the heap max size. No need to adjust
1763   // it with respect to the heap min size as it's a lower bound (i.e.,
1764   // we'll try to make the capacity larger than it, not smaller).
1765   minimum_desired_capacity = MIN2(minimum_desired_capacity, max_heap_size);
1766   // Should not be less than the heap min size. No need to adjust it
1767   // with respect to the heap max size as it's an upper bound (i.e.,
1768   // we'll try to make the capacity smaller than it, not greater).
1769   maximum_desired_capacity =  MAX2(maximum_desired_capacity, min_heap_size);
1770 
1771   if (capacity_after_gc < minimum_desired_capacity) {
1772     // Don't expand unless it's significant
1773     size_t expand_bytes = minimum_desired_capacity - capacity_after_gc;
1774     ergo_verbose4(ErgoHeapSizing,
1775                   "attempt heap expansion",
1776                   ergo_format_reason("capacity lower than "
1777                                      "min desired capacity after Full GC")
1778                   ergo_format_byte("capacity")
1779                   ergo_format_byte("occupancy")
1780                   ergo_format_byte_perc("min desired capacity"),
1781                   capacity_after_gc, used_after_gc,
1782                   minimum_desired_capacity, (double) MinHeapFreeRatio);
1783     expand(expand_bytes);
1784 
1785     // No expansion, now see if we want to shrink
1786   } else if (capacity_after_gc > maximum_desired_capacity) {
1787     // Capacity too large, compute shrinking size
1788     size_t shrink_bytes = capacity_after_gc - maximum_desired_capacity;
1789     ergo_verbose4(ErgoHeapSizing,
1790                   "attempt heap shrinking",
1791                   ergo_format_reason("capacity higher than "
1792                                      "max desired capacity after Full GC")
1793                   ergo_format_byte("capacity")
1794                   ergo_format_byte("occupancy")
1795                   ergo_format_byte_perc("max desired capacity"),
1796                   capacity_after_gc, used_after_gc,
1797                   maximum_desired_capacity, (double) MaxHeapFreeRatio);
1798     shrink(shrink_bytes);
1799   }
1800 }
1801 
1802 
1803 HeapWord*
1804 G1CollectedHeap::satisfy_failed_allocation(size_t word_size,
1805                                            AllocationContext_t context,
1806                                            bool* succeeded) {
1807   assert_at_safepoint(true /* should_be_vm_thread */);
1808 
1809   *succeeded = true;
1810   // Let's attempt the allocation first.
1811   HeapWord* result =
1812     attempt_allocation_at_safepoint(word_size,
1813                                     context,
1814                                     false /* expect_null_mutator_alloc_region */);
1815   if (result != NULL) {
1816     assert(*succeeded, "sanity");
1817     return result;
1818   }
1819 
1820   // In a G1 heap, we're supposed to keep allocation from failing by
1821   // incremental pauses.  Therefore, at least for now, we'll favor
1822   // expansion over collection.  (This might change in the future if we can
1823   // do something smarter than full collection to satisfy a failed alloc.)
1824   result = expand_and_allocate(word_size, context);
1825   if (result != NULL) {
1826     assert(*succeeded, "sanity");
1827     return result;
1828   }
1829 
1830   // Expansion didn't work, we'll try to do a Full GC.
1831   bool gc_succeeded = do_collection(false, /* explicit_gc */
1832                                     false, /* clear_all_soft_refs */
1833                                     word_size);
1834   if (!gc_succeeded) {
1835     *succeeded = false;
1836     return NULL;
1837   }
1838 
1839   // Retry the allocation
1840   result = attempt_allocation_at_safepoint(word_size,
1841                                            context,
1842                                            true /* expect_null_mutator_alloc_region */);
1843   if (result != NULL) {
1844     assert(*succeeded, "sanity");
1845     return result;
1846   }
1847 
1848   // Then, try a Full GC that will collect all soft references.
1849   gc_succeeded = do_collection(false, /* explicit_gc */
1850                                true,  /* clear_all_soft_refs */
1851                                word_size);
1852   if (!gc_succeeded) {
1853     *succeeded = false;
1854     return NULL;
1855   }
1856 
1857   // Retry the allocation once more
1858   result = attempt_allocation_at_safepoint(word_size,
1859                                            context,
1860                                            true /* expect_null_mutator_alloc_region */);
1861   if (result != NULL) {
1862     assert(*succeeded, "sanity");
1863     return result;
1864   }
1865 
1866   assert(!collector_policy()->should_clear_all_soft_refs(),
1867          "Flag should have been handled and cleared prior to this point");
1868 
1869   // What else?  We might try synchronous finalization later.  If the total
1870   // space available is large enough for the allocation, then a more
1871   // complete compaction phase than we've tried so far might be
1872   // appropriate.
1873   assert(*succeeded, "sanity");
1874   return NULL;
1875 }
1876 
1877 // Attempting to expand the heap sufficiently
1878 // to support an allocation of the given "word_size".  If
1879 // successful, perform the allocation and return the address of the
1880 // allocated block, or else "NULL".
1881 
1882 HeapWord* G1CollectedHeap::expand_and_allocate(size_t word_size, AllocationContext_t context) {
1883   assert_at_safepoint(true /* should_be_vm_thread */);
1884 
1885   verify_region_sets_optional();
1886 
1887   size_t expand_bytes = MAX2(word_size * HeapWordSize, MinHeapDeltaBytes);
1888   ergo_verbose1(ErgoHeapSizing,
1889                 "attempt heap expansion",
1890                 ergo_format_reason("allocation request failed")
1891                 ergo_format_byte("allocation request"),
1892                 word_size * HeapWordSize);
1893   if (expand(expand_bytes)) {
1894     _hrm.verify_optional();
1895     verify_region_sets_optional();
1896     return attempt_allocation_at_safepoint(word_size,
1897                                            context,
1898                                            false /* expect_null_mutator_alloc_region */);
1899   }
1900   return NULL;
1901 }
1902 
1903 bool G1CollectedHeap::expand(size_t expand_bytes) {
1904   size_t aligned_expand_bytes = ReservedSpace::page_align_size_up(expand_bytes);
1905   aligned_expand_bytes = align_size_up(aligned_expand_bytes,
1906                                        HeapRegion::GrainBytes);
1907   ergo_verbose2(ErgoHeapSizing,
1908                 "expand the heap",
1909                 ergo_format_byte("requested expansion amount")
1910                 ergo_format_byte("attempted expansion amount"),
1911                 expand_bytes, aligned_expand_bytes);
1912 
1913   if (is_maximal_no_gc()) {
1914     ergo_verbose0(ErgoHeapSizing,
1915                       "did not expand the heap",
1916                       ergo_format_reason("heap already fully expanded"));
1917     return false;
1918   }
1919 
1920   uint regions_to_expand = (uint)(aligned_expand_bytes / HeapRegion::GrainBytes);
1921   assert(regions_to_expand > 0, "Must expand by at least one region");
1922 
1923   uint expanded_by = _hrm.expand_by(regions_to_expand);
1924 
1925   if (expanded_by > 0) {
1926     size_t actual_expand_bytes = expanded_by * HeapRegion::GrainBytes;
1927     assert(actual_expand_bytes <= aligned_expand_bytes, "post-condition");
1928     g1_policy()->record_new_heap_size(num_regions());
1929   } else {
1930     ergo_verbose0(ErgoHeapSizing,
1931                   "did not expand the heap",
1932                   ergo_format_reason("heap expansion operation failed"));
1933     // The expansion of the virtual storage space was unsuccessful.
1934     // Let's see if it was because we ran out of swap.
1935     if (G1ExitOnExpansionFailure &&
1936         _hrm.available() >= regions_to_expand) {
1937       // We had head room...
1938       vm_exit_out_of_memory(aligned_expand_bytes, OOM_MMAP_ERROR, "G1 heap expansion");
1939     }
1940   }
1941   return regions_to_expand > 0;
1942 }
1943 
1944 void G1CollectedHeap::shrink_helper(size_t shrink_bytes) {
1945   size_t aligned_shrink_bytes =
1946     ReservedSpace::page_align_size_down(shrink_bytes);
1947   aligned_shrink_bytes = align_size_down(aligned_shrink_bytes,
1948                                          HeapRegion::GrainBytes);
1949   uint num_regions_to_remove = (uint)(shrink_bytes / HeapRegion::GrainBytes);
1950 
1951   uint num_regions_removed = _hrm.shrink_by(num_regions_to_remove);
1952   size_t shrunk_bytes = num_regions_removed * HeapRegion::GrainBytes;
1953 
1954   ergo_verbose3(ErgoHeapSizing,
1955                 "shrink the heap",
1956                 ergo_format_byte("requested shrinking amount")
1957                 ergo_format_byte("aligned shrinking amount")
1958                 ergo_format_byte("attempted shrinking amount"),
1959                 shrink_bytes, aligned_shrink_bytes, shrunk_bytes);
1960   if (num_regions_removed > 0) {
1961     g1_policy()->record_new_heap_size(num_regions());
1962   } else {
1963     ergo_verbose0(ErgoHeapSizing,
1964                   "did not shrink the heap",
1965                   ergo_format_reason("heap shrinking operation failed"));
1966   }
1967 }
1968 
1969 void G1CollectedHeap::shrink(size_t shrink_bytes) {
1970   verify_region_sets_optional();
1971 
1972   // We should only reach here at the end of a Full GC which means we
1973   // should not not be holding to any GC alloc regions. The method
1974   // below will make sure of that and do any remaining clean up.
1975   _allocator->abandon_gc_alloc_regions();
1976 
1977   // Instead of tearing down / rebuilding the free lists here, we
1978   // could instead use the remove_all_pending() method on free_list to
1979   // remove only the ones that we need to remove.
1980   tear_down_region_sets(true /* free_list_only */);
1981   shrink_helper(shrink_bytes);
1982   rebuild_region_sets(true /* free_list_only */);
1983 
1984   _hrm.verify_optional();
1985   verify_region_sets_optional();
1986 }
1987 
1988 // Public methods.
1989 
1990 #ifdef _MSC_VER // the use of 'this' below gets a warning, make it go away
1991 #pragma warning( disable:4355 ) // 'this' : used in base member initializer list
1992 #endif // _MSC_VER
1993 
1994 
1995 G1CollectedHeap::G1CollectedHeap(G1CollectorPolicy* policy_) :
1996   CollectedHeap(),
1997   _g1_policy(policy_),
1998   _dirty_card_queue_set(false),
1999   _into_cset_dirty_card_queue_set(false),
2000   _is_alive_closure_cm(this),
2001   _is_alive_closure_stw(this),
2002   _ref_processor_cm(NULL),
2003   _ref_processor_stw(NULL),
2004   _bot_shared(NULL),
2005   _cg1r(NULL),
2006   _g1mm(NULL),
2007   _refine_cte_cl(NULL),
2008   _secondary_free_list("Secondary Free List", new SecondaryFreeRegionListMtSafeChecker()),
2009   _old_set("Old Set", false /* humongous */, new OldRegionSetMtSafeChecker()),
2010   _humongous_set("Master Humongous Set", true /* humongous */, new HumongousRegionSetMtSafeChecker()),
2011   _humongous_reclaim_candidates(),
2012   _has_humongous_reclaim_candidates(false),
2013   _archive_allocator(NULL),
2014   _free_regions_coming(false),
2015   _young_list(new YoungList(this)),
2016   _gc_time_stamp(0),
2017   _summary_bytes_used(0),
2018   _survivor_evac_stats(YoungPLABSize, PLABWeight),
2019   _old_evac_stats(OldPLABSize, PLABWeight),
2020   _expand_heap_after_alloc_failure(true),
2021   _old_marking_cycles_started(0),
2022   _old_marking_cycles_completed(0),
2023   _heap_summary_sent(false),
2024   _in_cset_fast_test(),
2025   _dirty_cards_region_list(NULL),
2026   _worker_cset_start_region(NULL),
2027   _worker_cset_start_region_time_stamp(NULL),
2028   _gc_timer_stw(new (ResourceObj::C_HEAP, mtGC) STWGCTimer()),
2029   _gc_timer_cm(new (ResourceObj::C_HEAP, mtGC) ConcurrentGCTimer()),
2030   _gc_tracer_stw(new (ResourceObj::C_HEAP, mtGC) G1NewTracer()),
2031   _gc_tracer_cm(new (ResourceObj::C_HEAP, mtGC) G1OldTracer()) {
2032 
2033   _workers = new WorkGang("GC Thread", ParallelGCThreads,
2034                           /* are_GC_task_threads */true,
2035                           /* are_ConcurrentGC_threads */false);
2036   _workers->initialize_workers();
2037 
2038   _allocator = G1Allocator::create_allocator(this);
2039   _humongous_object_threshold_in_words = humongous_threshold_for(HeapRegion::GrainWords);
2040 
2041   // Override the default _filler_array_max_size so that no humongous filler
2042   // objects are created.
2043   _filler_array_max_size = _humongous_object_threshold_in_words;
2044 
2045   uint n_queues = ParallelGCThreads;
2046   _task_queues = new RefToScanQueueSet(n_queues);
2047 
2048   uint n_rem_sets = HeapRegionRemSet::num_par_rem_sets();
2049   assert(n_rem_sets > 0, "Invariant.");
2050 
2051   _worker_cset_start_region = NEW_C_HEAP_ARRAY(HeapRegion*, n_queues, mtGC);
2052   _worker_cset_start_region_time_stamp = NEW_C_HEAP_ARRAY(uint, n_queues, mtGC);
2053   _evacuation_failed_info_array = NEW_C_HEAP_ARRAY(EvacuationFailedInfo, n_queues, mtGC);
2054 
2055   for (uint i = 0; i < n_queues; i++) {
2056     RefToScanQueue* q = new RefToScanQueue();
2057     q->initialize();
2058     _task_queues->register_queue(i, q);
2059     ::new (&_evacuation_failed_info_array[i]) EvacuationFailedInfo();
2060   }
2061   clear_cset_start_regions();
2062 
2063   // Initialize the G1EvacuationFailureALot counters and flags.
2064   NOT_PRODUCT(reset_evacuation_should_fail();)
2065 
2066   guarantee(_task_queues != NULL, "task_queues allocation failure.");
2067 }
2068 
2069 G1RegionToSpaceMapper* G1CollectedHeap::create_aux_memory_mapper(const char* description,
2070                                                                  size_t size,
2071                                                                  size_t translation_factor) {
2072   size_t preferred_page_size = os::page_size_for_region_unaligned(size, 1);
2073   // Allocate a new reserved space, preferring to use large pages.
2074   ReservedSpace rs(size, preferred_page_size);
2075   G1RegionToSpaceMapper* result  =
2076     G1RegionToSpaceMapper::create_mapper(rs,
2077                                          size,
2078                                          rs.alignment(),
2079                                          HeapRegion::GrainBytes,
2080                                          translation_factor,
2081                                          mtGC);
2082   if (TracePageSizes) {
2083     gclog_or_tty->print_cr("G1 '%s': pg_sz=" SIZE_FORMAT " base=" PTR_FORMAT " size=" SIZE_FORMAT " alignment=" SIZE_FORMAT " reqsize=" SIZE_FORMAT,
2084                            description, preferred_page_size, p2i(rs.base()), rs.size(), rs.alignment(), size);
2085   }
2086   return result;
2087 }
2088 
2089 jint G1CollectedHeap::initialize() {
2090   CollectedHeap::pre_initialize();
2091   os::enable_vtime();
2092 
2093   G1Log::init();
2094 
2095   // Necessary to satisfy locking discipline assertions.
2096 
2097   MutexLocker x(Heap_lock);
2098 
2099   // We have to initialize the printer before committing the heap, as
2100   // it will be used then.
2101   _hr_printer.set_active(G1PrintHeapRegions);
2102 
2103   // While there are no constraints in the GC code that HeapWordSize
2104   // be any particular value, there are multiple other areas in the
2105   // system which believe this to be true (e.g. oop->object_size in some
2106   // cases incorrectly returns the size in wordSize units rather than
2107   // HeapWordSize).
2108   guarantee(HeapWordSize == wordSize, "HeapWordSize must equal wordSize");
2109 
2110   size_t init_byte_size = collector_policy()->initial_heap_byte_size();
2111   size_t max_byte_size = collector_policy()->max_heap_byte_size();
2112   size_t heap_alignment = collector_policy()->heap_alignment();
2113 
2114   // Ensure that the sizes are properly aligned.
2115   Universe::check_alignment(init_byte_size, HeapRegion::GrainBytes, "g1 heap");
2116   Universe::check_alignment(max_byte_size, HeapRegion::GrainBytes, "g1 heap");
2117   Universe::check_alignment(max_byte_size, heap_alignment, "g1 heap");
2118 
2119   _refine_cte_cl = new RefineCardTableEntryClosure();
2120 
2121   jint ecode = JNI_OK;
2122   _cg1r = ConcurrentG1Refine::create(this, _refine_cte_cl, &ecode);
2123   if (_cg1r == NULL) {
2124     return ecode;
2125   }
2126 
2127   // Reserve the maximum.
2128 
2129   // When compressed oops are enabled, the preferred heap base
2130   // is calculated by subtracting the requested size from the
2131   // 32Gb boundary and using the result as the base address for
2132   // heap reservation. If the requested size is not aligned to
2133   // HeapRegion::GrainBytes (i.e. the alignment that is passed
2134   // into the ReservedHeapSpace constructor) then the actual
2135   // base of the reserved heap may end up differing from the
2136   // address that was requested (i.e. the preferred heap base).
2137   // If this happens then we could end up using a non-optimal
2138   // compressed oops mode.
2139 
2140   ReservedSpace heap_rs = Universe::reserve_heap(max_byte_size,
2141                                                  heap_alignment);
2142 
2143   initialize_reserved_region((HeapWord*)heap_rs.base(), (HeapWord*)(heap_rs.base() + heap_rs.size()));
2144 
2145   // Create the barrier set for the entire reserved region.
2146   G1SATBCardTableLoggingModRefBS* bs
2147     = new G1SATBCardTableLoggingModRefBS(reserved_region());
2148   bs->initialize();
2149   assert(bs->is_a(BarrierSet::G1SATBCTLogging), "sanity");
2150   set_barrier_set(bs);
2151 
2152   // Also create a G1 rem set.
2153   _g1_rem_set = new G1RemSet(this, g1_barrier_set());
2154 
2155   // Carve out the G1 part of the heap.
2156 
2157   ReservedSpace g1_rs = heap_rs.first_part(max_byte_size);
2158   size_t page_size = UseLargePages ? os::large_page_size() : os::vm_page_size();
2159   G1RegionToSpaceMapper* heap_storage =
2160     G1RegionToSpaceMapper::create_mapper(g1_rs,
2161                                          g1_rs.size(),
2162                                          page_size,
2163                                          HeapRegion::GrainBytes,
2164                                          1,
2165                                          mtJavaHeap);
2166   os::trace_page_sizes("G1 Heap", collector_policy()->min_heap_byte_size(),
2167                        max_byte_size, page_size,
2168                        heap_rs.base(),
2169                        heap_rs.size());
2170   heap_storage->set_mapping_changed_listener(&_listener);
2171 
2172   // Create storage for the BOT, card table, card counts table (hot card cache) and the bitmaps.
2173   G1RegionToSpaceMapper* bot_storage =
2174     create_aux_memory_mapper("Block offset table",
2175                              G1BlockOffsetSharedArray::compute_size(g1_rs.size() / HeapWordSize),
2176                              G1BlockOffsetSharedArray::heap_map_factor());
2177 
2178   ReservedSpace cardtable_rs(G1SATBCardTableLoggingModRefBS::compute_size(g1_rs.size() / HeapWordSize));
2179   G1RegionToSpaceMapper* cardtable_storage =
2180     create_aux_memory_mapper("Card table",
2181                              G1SATBCardTableLoggingModRefBS::compute_size(g1_rs.size() / HeapWordSize),
2182                              G1SATBCardTableLoggingModRefBS::heap_map_factor());
2183 
2184   G1RegionToSpaceMapper* card_counts_storage =
2185     create_aux_memory_mapper("Card counts table",
2186                              G1CardCounts::compute_size(g1_rs.size() / HeapWordSize),
2187                              G1CardCounts::heap_map_factor());
2188 
2189   size_t bitmap_size = CMBitMap::compute_size(g1_rs.size());
2190   G1RegionToSpaceMapper* prev_bitmap_storage =
2191     create_aux_memory_mapper("Prev Bitmap", bitmap_size, CMBitMap::heap_map_factor());
2192   G1RegionToSpaceMapper* next_bitmap_storage =
2193     create_aux_memory_mapper("Next Bitmap", bitmap_size, CMBitMap::heap_map_factor());
2194 
2195   _hrm.initialize(heap_storage, prev_bitmap_storage, next_bitmap_storage, bot_storage, cardtable_storage, card_counts_storage);
2196   g1_barrier_set()->initialize(cardtable_storage);
2197    // Do later initialization work for concurrent refinement.
2198   _cg1r->init(card_counts_storage);
2199 
2200   // 6843694 - ensure that the maximum region index can fit
2201   // in the remembered set structures.
2202   const uint max_region_idx = (1U << (sizeof(RegionIdx_t)*BitsPerByte-1)) - 1;
2203   guarantee((max_regions() - 1) <= max_region_idx, "too many regions");
2204 
2205   size_t max_cards_per_region = ((size_t)1 << (sizeof(CardIdx_t)*BitsPerByte-1)) - 1;
2206   guarantee(HeapRegion::CardsPerRegion > 0, "make sure it's initialized");
2207   guarantee(HeapRegion::CardsPerRegion < max_cards_per_region,
2208             "too many cards per region");
2209 
2210   FreeRegionList::set_unrealistically_long_length(max_regions() + 1);
2211 
2212   _bot_shared = new G1BlockOffsetSharedArray(reserved_region(), bot_storage);
2213 
2214   {
2215     HeapWord* start = _hrm.reserved().start();
2216     HeapWord* end = _hrm.reserved().end();
2217     size_t granularity = HeapRegion::GrainBytes;
2218 
2219     _in_cset_fast_test.initialize(start, end, granularity);
2220     _humongous_reclaim_candidates.initialize(start, end, granularity);
2221   }
2222 
2223   // Create the ConcurrentMark data structure and thread.
2224   // (Must do this late, so that "max_regions" is defined.)
2225   _cm = new ConcurrentMark(this, prev_bitmap_storage, next_bitmap_storage);
2226   if (_cm == NULL || !_cm->completed_initialization()) {
2227     vm_shutdown_during_initialization("Could not create/initialize ConcurrentMark");
2228     return JNI_ENOMEM;
2229   }
2230   _cmThread = _cm->cmThread();
2231 
2232   // Initialize the from_card cache structure of HeapRegionRemSet.
2233   HeapRegionRemSet::init_heap(max_regions());
2234 
2235   // Now expand into the initial heap size.
2236   if (!expand(init_byte_size)) {
2237     vm_shutdown_during_initialization("Failed to allocate initial heap.");
2238     return JNI_ENOMEM;
2239   }
2240 
2241   // Perform any initialization actions delegated to the policy.
2242   g1_policy()->init();
2243 
2244   JavaThread::satb_mark_queue_set().initialize(SATB_Q_CBL_mon,
2245                                                SATB_Q_FL_lock,
2246                                                G1SATBProcessCompletedThreshold,
2247                                                Shared_SATB_Q_lock);
2248 
2249   JavaThread::dirty_card_queue_set().initialize(_refine_cte_cl,
2250                                                 DirtyCardQ_CBL_mon,
2251                                                 DirtyCardQ_FL_lock,
2252                                                 concurrent_g1_refine()->yellow_zone(),
2253                                                 concurrent_g1_refine()->red_zone(),
2254                                                 Shared_DirtyCardQ_lock);
2255 
2256   dirty_card_queue_set().initialize(NULL, // Should never be called by the Java code
2257                                     DirtyCardQ_CBL_mon,
2258                                     DirtyCardQ_FL_lock,
2259                                     -1, // never trigger processing
2260                                     -1, // no limit on length
2261                                     Shared_DirtyCardQ_lock,
2262                                     &JavaThread::dirty_card_queue_set());
2263 
2264   // Initialize the card queue set used to hold cards containing
2265   // references into the collection set.
2266   _into_cset_dirty_card_queue_set.initialize(NULL, // Should never be called by the Java code
2267                                              DirtyCardQ_CBL_mon,
2268                                              DirtyCardQ_FL_lock,
2269                                              -1, // never trigger processing
2270                                              -1, // no limit on length
2271                                              Shared_DirtyCardQ_lock,
2272                                              &JavaThread::dirty_card_queue_set());
2273 
2274   // Here we allocate the dummy HeapRegion that is required by the
2275   // G1AllocRegion class.
2276   HeapRegion* dummy_region = _hrm.get_dummy_region();
2277 
2278   // We'll re-use the same region whether the alloc region will
2279   // require BOT updates or not and, if it doesn't, then a non-young
2280   // region will complain that it cannot support allocations without
2281   // BOT updates. So we'll tag the dummy region as eden to avoid that.
2282   dummy_region->set_eden();
2283   // Make sure it's full.
2284   dummy_region->set_top(dummy_region->end());
2285   G1AllocRegion::setup(this, dummy_region);
2286 
2287   _allocator->init_mutator_alloc_region();
2288 
2289   // Do create of the monitoring and management support so that
2290   // values in the heap have been properly initialized.
2291   _g1mm = new G1MonitoringSupport(this);
2292 
2293   G1StringDedup::initialize();
2294 
2295   _preserved_objs = NEW_C_HEAP_ARRAY(OopAndMarkOopStack, ParallelGCThreads, mtGC);
2296   for (uint i = 0; i < ParallelGCThreads; i++) {
2297     new (&_preserved_objs[i]) OopAndMarkOopStack();
2298   }
2299 
2300   return JNI_OK;
2301 }
2302 
2303 void G1CollectedHeap::stop() {
2304   // Stop all concurrent threads. We do this to make sure these threads
2305   // do not continue to execute and access resources (e.g. gclog_or_tty)
2306   // that are destroyed during shutdown.
2307   _cg1r->stop();
2308   _cmThread->stop();
2309   if (G1StringDedup::is_enabled()) {
2310     G1StringDedup::stop();
2311   }
2312 }
2313 
2314 size_t G1CollectedHeap::conservative_max_heap_alignment() {
2315   return HeapRegion::max_region_size();
2316 }
2317 
2318 void G1CollectedHeap::post_initialize() {
2319   CollectedHeap::post_initialize();
2320   ref_processing_init();
2321 }
2322 
2323 void G1CollectedHeap::ref_processing_init() {
2324   // Reference processing in G1 currently works as follows:
2325   //
2326   // * There are two reference processor instances. One is
2327   //   used to record and process discovered references
2328   //   during concurrent marking; the other is used to
2329   //   record and process references during STW pauses
2330   //   (both full and incremental).
2331   // * Both ref processors need to 'span' the entire heap as
2332   //   the regions in the collection set may be dotted around.
2333   //
2334   // * For the concurrent marking ref processor:
2335   //   * Reference discovery is enabled at initial marking.
2336   //   * Reference discovery is disabled and the discovered
2337   //     references processed etc during remarking.
2338   //   * Reference discovery is MT (see below).
2339   //   * Reference discovery requires a barrier (see below).
2340   //   * Reference processing may or may not be MT
2341   //     (depending on the value of ParallelRefProcEnabled
2342   //     and ParallelGCThreads).
2343   //   * A full GC disables reference discovery by the CM
2344   //     ref processor and abandons any entries on it's
2345   //     discovered lists.
2346   //
2347   // * For the STW processor:
2348   //   * Non MT discovery is enabled at the start of a full GC.
2349   //   * Processing and enqueueing during a full GC is non-MT.
2350   //   * During a full GC, references are processed after marking.
2351   //
2352   //   * Discovery (may or may not be MT) is enabled at the start
2353   //     of an incremental evacuation pause.
2354   //   * References are processed near the end of a STW evacuation pause.
2355   //   * For both types of GC:
2356   //     * Discovery is atomic - i.e. not concurrent.
2357   //     * Reference discovery will not need a barrier.
2358 
2359   MemRegion mr = reserved_region();
2360 
2361   // Concurrent Mark ref processor
2362   _ref_processor_cm =
2363     new ReferenceProcessor(mr,    // span
2364                            ParallelRefProcEnabled && (ParallelGCThreads > 1),
2365                                 // mt processing
2366                            ParallelGCThreads,
2367                                 // degree of mt processing
2368                            (ParallelGCThreads > 1) || (ConcGCThreads > 1),
2369                                 // mt discovery
2370                            MAX2(ParallelGCThreads, ConcGCThreads),
2371                                 // degree of mt discovery
2372                            false,
2373                                 // Reference discovery is not atomic
2374                            &_is_alive_closure_cm);
2375                                 // is alive closure
2376                                 // (for efficiency/performance)
2377 
2378   // STW ref processor
2379   _ref_processor_stw =
2380     new ReferenceProcessor(mr,    // span
2381                            ParallelRefProcEnabled && (ParallelGCThreads > 1),
2382                                 // mt processing
2383                            ParallelGCThreads,
2384                                 // degree of mt processing
2385                            (ParallelGCThreads > 1),
2386                                 // mt discovery
2387                            ParallelGCThreads,
2388                                 // degree of mt discovery
2389                            true,
2390                                 // Reference discovery is atomic
2391                            &_is_alive_closure_stw);
2392                                 // is alive closure
2393                                 // (for efficiency/performance)
2394 }
2395 
2396 CollectorPolicy* G1CollectedHeap::collector_policy() const {
2397   return g1_policy();
2398 }
2399 
2400 size_t G1CollectedHeap::capacity() const {
2401   return _hrm.length() * HeapRegion::GrainBytes;
2402 }
2403 
2404 void G1CollectedHeap::reset_gc_time_stamps(HeapRegion* hr) {
2405   assert(!hr->is_continues_humongous(), "pre-condition");
2406   hr->reset_gc_time_stamp();
2407   if (hr->is_starts_humongous()) {
2408     uint first_index = hr->hrm_index() + 1;
2409     uint last_index = hr->last_hc_index();
2410     for (uint i = first_index; i < last_index; i += 1) {
2411       HeapRegion* chr = region_at(i);
2412       assert(chr->is_continues_humongous(), "sanity");
2413       chr->reset_gc_time_stamp();
2414     }
2415   }
2416 }
2417 
2418 #ifndef PRODUCT
2419 
2420 class CheckGCTimeStampsHRClosure : public HeapRegionClosure {
2421 private:
2422   unsigned _gc_time_stamp;
2423   bool _failures;
2424 
2425 public:
2426   CheckGCTimeStampsHRClosure(unsigned gc_time_stamp) :
2427     _gc_time_stamp(gc_time_stamp), _failures(false) { }
2428 
2429   virtual bool doHeapRegion(HeapRegion* hr) {
2430     unsigned region_gc_time_stamp = hr->get_gc_time_stamp();
2431     if (_gc_time_stamp != region_gc_time_stamp) {
2432       gclog_or_tty->print_cr("Region " HR_FORMAT " has GC time stamp = %d, "
2433                              "expected %d", HR_FORMAT_PARAMS(hr),
2434                              region_gc_time_stamp, _gc_time_stamp);
2435       _failures = true;
2436     }
2437     return false;
2438   }
2439 
2440   bool failures() { return _failures; }
2441 };
2442 
2443 void G1CollectedHeap::check_gc_time_stamps() {
2444   CheckGCTimeStampsHRClosure cl(_gc_time_stamp);
2445   heap_region_iterate(&cl);
2446   guarantee(!cl.failures(), "all GC time stamps should have been reset");
2447 }
2448 #endif // PRODUCT
2449 
2450 void G1CollectedHeap::iterate_dirty_card_closure(CardTableEntryClosure* cl,
2451                                                  DirtyCardQueue* into_cset_dcq,
2452                                                  bool concurrent,
2453                                                  uint worker_i) {
2454   // Clean cards in the hot card cache
2455   G1HotCardCache* hot_card_cache = _cg1r->hot_card_cache();
2456   hot_card_cache->drain(worker_i, g1_rem_set(), into_cset_dcq);
2457 
2458   DirtyCardQueueSet& dcqs = JavaThread::dirty_card_queue_set();
2459   size_t n_completed_buffers = 0;
2460   while (dcqs.apply_closure_to_completed_buffer(cl, worker_i, 0, true)) {
2461     n_completed_buffers++;
2462   }
2463   g1_policy()->phase_times()->record_thread_work_item(G1GCPhaseTimes::UpdateRS, worker_i, n_completed_buffers);
2464   dcqs.clear_n_completed_buffers();
2465   assert(!dcqs.completed_buffers_exist_dirty(), "Completed buffers exist!");
2466 }
2467 
2468 // Computes the sum of the storage used by the various regions.
2469 size_t G1CollectedHeap::used() const {
2470   size_t result = _summary_bytes_used + _allocator->used_in_alloc_regions();
2471   if (_archive_allocator != NULL) {
2472     result += _archive_allocator->used();
2473   }
2474   return result;
2475 }
2476 
2477 size_t G1CollectedHeap::used_unlocked() const {
2478   return _summary_bytes_used;
2479 }
2480 
2481 class SumUsedClosure: public HeapRegionClosure {
2482   size_t _used;
2483 public:
2484   SumUsedClosure() : _used(0) {}
2485   bool doHeapRegion(HeapRegion* r) {
2486     if (!r->is_continues_humongous()) {
2487       _used += r->used();
2488     }
2489     return false;
2490   }
2491   size_t result() { return _used; }
2492 };
2493 
2494 size_t G1CollectedHeap::recalculate_used() const {
2495   double recalculate_used_start = os::elapsedTime();
2496 
2497   SumUsedClosure blk;
2498   heap_region_iterate(&blk);
2499 
2500   g1_policy()->phase_times()->record_evac_fail_recalc_used_time((os::elapsedTime() - recalculate_used_start) * 1000.0);
2501   return blk.result();
2502 }
2503 
2504 bool G1CollectedHeap::should_do_concurrent_full_gc(GCCause::Cause cause) {
2505   switch (cause) {
2506     case GCCause::_gc_locker:               return GCLockerInvokesConcurrent;
2507     case GCCause::_java_lang_system_gc:     return ExplicitGCInvokesConcurrent;
2508     case GCCause::_dcmd_gc_run:             return ExplicitGCInvokesConcurrent;
2509     case GCCause::_g1_humongous_allocation: return true;
2510     case GCCause::_update_allocation_context_stats_inc: return true;
2511     case GCCause::_wb_conc_mark:            return true;
2512     default:                                return false;
2513   }
2514 }
2515 
2516 #ifndef PRODUCT
2517 void G1CollectedHeap::allocate_dummy_regions() {
2518   // Let's fill up most of the region
2519   size_t word_size = HeapRegion::GrainWords - 1024;
2520   // And as a result the region we'll allocate will be humongous.
2521   guarantee(is_humongous(word_size), "sanity");
2522 
2523   for (uintx i = 0; i < G1DummyRegionsPerGC; ++i) {
2524     // Let's use the existing mechanism for the allocation
2525     HeapWord* dummy_obj = humongous_obj_allocate(word_size,
2526                                                  AllocationContext::system());
2527     if (dummy_obj != NULL) {
2528       MemRegion mr(dummy_obj, word_size);
2529       CollectedHeap::fill_with_object(mr);
2530     } else {
2531       // If we can't allocate once, we probably cannot allocate
2532       // again. Let's get out of the loop.
2533       break;
2534     }
2535   }
2536 }
2537 #endif // !PRODUCT
2538 
2539 void G1CollectedHeap::increment_old_marking_cycles_started() {
2540   assert(_old_marking_cycles_started == _old_marking_cycles_completed ||
2541     _old_marking_cycles_started == _old_marking_cycles_completed + 1,
2542     err_msg("Wrong marking cycle count (started: %d, completed: %d)",
2543     _old_marking_cycles_started, _old_marking_cycles_completed));
2544 
2545   _old_marking_cycles_started++;
2546 }
2547 
2548 void G1CollectedHeap::increment_old_marking_cycles_completed(bool concurrent) {
2549   MonitorLockerEx x(FullGCCount_lock, Mutex::_no_safepoint_check_flag);
2550 
2551   // We assume that if concurrent == true, then the caller is a
2552   // concurrent thread that was joined the Suspendible Thread
2553   // Set. If there's ever a cheap way to check this, we should add an
2554   // assert here.
2555 
2556   // Given that this method is called at the end of a Full GC or of a
2557   // concurrent cycle, and those can be nested (i.e., a Full GC can
2558   // interrupt a concurrent cycle), the number of full collections
2559   // completed should be either one (in the case where there was no
2560   // nesting) or two (when a Full GC interrupted a concurrent cycle)
2561   // behind the number of full collections started.
2562 
2563   // This is the case for the inner caller, i.e. a Full GC.
2564   assert(concurrent ||
2565          (_old_marking_cycles_started == _old_marking_cycles_completed + 1) ||
2566          (_old_marking_cycles_started == _old_marking_cycles_completed + 2),
2567          err_msg("for inner caller (Full GC): _old_marking_cycles_started = %u "
2568                  "is inconsistent with _old_marking_cycles_completed = %u",
2569                  _old_marking_cycles_started, _old_marking_cycles_completed));
2570 
2571   // This is the case for the outer caller, i.e. the concurrent cycle.
2572   assert(!concurrent ||
2573          (_old_marking_cycles_started == _old_marking_cycles_completed + 1),
2574          err_msg("for outer caller (concurrent cycle): "
2575                  "_old_marking_cycles_started = %u "
2576                  "is inconsistent with _old_marking_cycles_completed = %u",
2577                  _old_marking_cycles_started, _old_marking_cycles_completed));
2578 
2579   _old_marking_cycles_completed += 1;
2580 
2581   // We need to clear the "in_progress" flag in the CM thread before
2582   // we wake up any waiters (especially when ExplicitInvokesConcurrent
2583   // is set) so that if a waiter requests another System.gc() it doesn't
2584   // incorrectly see that a marking cycle is still in progress.
2585   if (concurrent) {
2586     _cmThread->set_idle();
2587   }
2588 
2589   // This notify_all() will ensure that a thread that called
2590   // System.gc() with (with ExplicitGCInvokesConcurrent set or not)
2591   // and it's waiting for a full GC to finish will be woken up. It is
2592   // waiting in VM_G1IncCollectionPause::doit_epilogue().
2593   FullGCCount_lock->notify_all();
2594 }
2595 
2596 void G1CollectedHeap::register_concurrent_cycle_start(const Ticks& start_time) {
2597   collector_state()->set_concurrent_cycle_started(true);
2598   _gc_timer_cm->register_gc_start(start_time);
2599 
2600   _gc_tracer_cm->report_gc_start(gc_cause(), _gc_timer_cm->gc_start());
2601   trace_heap_before_gc(_gc_tracer_cm);
2602 }
2603 
2604 void G1CollectedHeap::register_concurrent_cycle_end() {
2605   if (collector_state()->concurrent_cycle_started()) {
2606     if (_cm->has_aborted()) {
2607       _gc_tracer_cm->report_concurrent_mode_failure();
2608     }
2609 
2610     _gc_timer_cm->register_gc_end();
2611     _gc_tracer_cm->report_gc_end(_gc_timer_cm->gc_end(), _gc_timer_cm->time_partitions());
2612 
2613     // Clear state variables to prepare for the next concurrent cycle.
2614      collector_state()->set_concurrent_cycle_started(false);
2615     _heap_summary_sent = false;
2616   }
2617 }
2618 
2619 void G1CollectedHeap::trace_heap_after_concurrent_cycle() {
2620   if (collector_state()->concurrent_cycle_started()) {
2621     // This function can be called when:
2622     //  the cleanup pause is run
2623     //  the concurrent cycle is aborted before the cleanup pause.
2624     //  the concurrent cycle is aborted after the cleanup pause,
2625     //   but before the concurrent cycle end has been registered.
2626     // Make sure that we only send the heap information once.
2627     if (!_heap_summary_sent) {
2628       trace_heap_after_gc(_gc_tracer_cm);
2629       _heap_summary_sent = true;
2630     }
2631   }
2632 }
2633 
2634 void G1CollectedHeap::collect(GCCause::Cause cause) {
2635   assert_heap_not_locked();
2636 
2637   uint gc_count_before;
2638   uint old_marking_count_before;
2639   uint full_gc_count_before;
2640   bool retry_gc;
2641 
2642   do {
2643     retry_gc = false;
2644 
2645     {
2646       MutexLocker ml(Heap_lock);
2647 
2648       // Read the GC count while holding the Heap_lock
2649       gc_count_before = total_collections();
2650       full_gc_count_before = total_full_collections();
2651       old_marking_count_before = _old_marking_cycles_started;
2652     }
2653 
2654     if (should_do_concurrent_full_gc(cause)) {
2655       // Schedule an initial-mark evacuation pause that will start a
2656       // concurrent cycle. We're setting word_size to 0 which means that
2657       // we are not requesting a post-GC allocation.
2658       VM_G1IncCollectionPause op(gc_count_before,
2659                                  0,     /* word_size */
2660                                  true,  /* should_initiate_conc_mark */
2661                                  g1_policy()->max_pause_time_ms(),
2662                                  cause);
2663       op.set_allocation_context(AllocationContext::current());
2664 
2665       VMThread::execute(&op);
2666       if (!op.pause_succeeded()) {
2667         if (old_marking_count_before == _old_marking_cycles_started) {
2668           retry_gc = op.should_retry_gc();
2669         } else {
2670           // A Full GC happened while we were trying to schedule the
2671           // initial-mark GC. No point in starting a new cycle given
2672           // that the whole heap was collected anyway.
2673         }
2674 
2675         if (retry_gc) {
2676           if (GC_locker::is_active_and_needs_gc()) {
2677             GC_locker::stall_until_clear();
2678           }
2679         }
2680       }
2681     } else {
2682       if (cause == GCCause::_gc_locker || cause == GCCause::_wb_young_gc
2683           DEBUG_ONLY(|| cause == GCCause::_scavenge_alot)) {
2684 
2685         // Schedule a standard evacuation pause. We're setting word_size
2686         // to 0 which means that we are not requesting a post-GC allocation.
2687         VM_G1IncCollectionPause op(gc_count_before,
2688                                    0,     /* word_size */
2689                                    false, /* should_initiate_conc_mark */
2690                                    g1_policy()->max_pause_time_ms(),
2691                                    cause);
2692         VMThread::execute(&op);
2693       } else {
2694         // Schedule a Full GC.
2695         VM_G1CollectFull op(gc_count_before, full_gc_count_before, cause);
2696         VMThread::execute(&op);
2697       }
2698     }
2699   } while (retry_gc);
2700 }
2701 
2702 bool G1CollectedHeap::is_in(const void* p) const {
2703   if (_hrm.reserved().contains(p)) {
2704     // Given that we know that p is in the reserved space,
2705     // heap_region_containing_raw() should successfully
2706     // return the containing region.
2707     HeapRegion* hr = heap_region_containing_raw(p);
2708     return hr->is_in(p);
2709   } else {
2710     return false;
2711   }
2712 }
2713 
2714 #ifdef ASSERT
2715 bool G1CollectedHeap::is_in_exact(const void* p) const {
2716   bool contains = reserved_region().contains(p);
2717   bool available = _hrm.is_available(addr_to_region((HeapWord*)p));
2718   if (contains && available) {
2719     return true;
2720   } else {
2721     return false;
2722   }
2723 }
2724 #endif
2725 
2726 bool G1CollectedHeap::obj_in_cs(oop obj) {
2727   HeapRegion* r = _hrm.addr_to_region((HeapWord*) obj);
2728   return r != NULL && r->in_collection_set();
2729 }
2730 
2731 // Iteration functions.
2732 
2733 // Applies an ExtendedOopClosure onto all references of objects within a HeapRegion.
2734 
2735 class IterateOopClosureRegionClosure: public HeapRegionClosure {
2736   ExtendedOopClosure* _cl;
2737 public:
2738   IterateOopClosureRegionClosure(ExtendedOopClosure* cl) : _cl(cl) {}
2739   bool doHeapRegion(HeapRegion* r) {
2740     if (!r->is_continues_humongous()) {
2741       r->oop_iterate(_cl);
2742     }
2743     return false;
2744   }
2745 };
2746 
2747 // Iterates an ObjectClosure over all objects within a HeapRegion.
2748 
2749 class IterateObjectClosureRegionClosure: public HeapRegionClosure {
2750   ObjectClosure* _cl;
2751 public:
2752   IterateObjectClosureRegionClosure(ObjectClosure* cl) : _cl(cl) {}
2753   bool doHeapRegion(HeapRegion* r) {
2754     if (!r->is_continues_humongous()) {
2755       r->object_iterate(_cl);
2756     }
2757     return false;
2758   }
2759 };
2760 
2761 void G1CollectedHeap::object_iterate(ObjectClosure* cl) {
2762   IterateObjectClosureRegionClosure blk(cl);
2763   heap_region_iterate(&blk);
2764 }
2765 
2766 void G1CollectedHeap::heap_region_iterate(HeapRegionClosure* cl) const {
2767   _hrm.iterate(cl);
2768 }
2769 
2770 void
2771 G1CollectedHeap::heap_region_par_iterate(HeapRegionClosure* cl,
2772                                          uint worker_id,
2773                                          HeapRegionClaimer *hrclaimer,
2774                                          bool concurrent) const {
2775   _hrm.par_iterate(cl, worker_id, hrclaimer, concurrent);
2776 }
2777 
2778 // Clear the cached CSet starting regions and (more importantly)
2779 // the time stamps. Called when we reset the GC time stamp.
2780 void G1CollectedHeap::clear_cset_start_regions() {
2781   assert(_worker_cset_start_region != NULL, "sanity");
2782   assert(_worker_cset_start_region_time_stamp != NULL, "sanity");
2783 
2784   for (uint i = 0; i < ParallelGCThreads; i++) {
2785     _worker_cset_start_region[i] = NULL;
2786     _worker_cset_start_region_time_stamp[i] = 0;
2787   }
2788 }
2789 
2790 // Given the id of a worker, obtain or calculate a suitable
2791 // starting region for iterating over the current collection set.
2792 HeapRegion* G1CollectedHeap::start_cset_region_for_worker(uint worker_i) {
2793   assert(get_gc_time_stamp() > 0, "should have been updated by now");
2794 
2795   HeapRegion* result = NULL;
2796   unsigned gc_time_stamp = get_gc_time_stamp();
2797 
2798   if (_worker_cset_start_region_time_stamp[worker_i] == gc_time_stamp) {
2799     // Cached starting region for current worker was set
2800     // during the current pause - so it's valid.
2801     // Note: the cached starting heap region may be NULL
2802     // (when the collection set is empty).
2803     result = _worker_cset_start_region[worker_i];
2804     assert(result == NULL || result->in_collection_set(), "sanity");
2805     return result;
2806   }
2807 
2808   // The cached entry was not valid so let's calculate
2809   // a suitable starting heap region for this worker.
2810 
2811   // We want the parallel threads to start their collection
2812   // set iteration at different collection set regions to
2813   // avoid contention.
2814   // If we have:
2815   //          n collection set regions
2816   //          p threads
2817   // Then thread t will start at region floor ((t * n) / p)
2818 
2819   result = g1_policy()->collection_set();
2820   uint cs_size = g1_policy()->cset_region_length();
2821   uint active_workers = workers()->active_workers();
2822 
2823   uint end_ind   = (cs_size * worker_i) / active_workers;
2824   uint start_ind = 0;
2825 
2826   if (worker_i > 0 &&
2827       _worker_cset_start_region_time_stamp[worker_i - 1] == gc_time_stamp) {
2828     // Previous workers starting region is valid
2829     // so let's iterate from there
2830     start_ind = (cs_size * (worker_i - 1)) / active_workers;
2831     result = _worker_cset_start_region[worker_i - 1];
2832   }
2833 
2834   for (uint i = start_ind; i < end_ind; i++) {
2835     result = result->next_in_collection_set();
2836   }
2837 
2838   // Note: the calculated starting heap region may be NULL
2839   // (when the collection set is empty).
2840   assert(result == NULL || result->in_collection_set(), "sanity");
2841   assert(_worker_cset_start_region_time_stamp[worker_i] != gc_time_stamp,
2842          "should be updated only once per pause");
2843   _worker_cset_start_region[worker_i] = result;
2844   OrderAccess::storestore();
2845   _worker_cset_start_region_time_stamp[worker_i] = gc_time_stamp;
2846   return result;
2847 }
2848 
2849 void G1CollectedHeap::collection_set_iterate(HeapRegionClosure* cl) {
2850   HeapRegion* r = g1_policy()->collection_set();
2851   while (r != NULL) {
2852     HeapRegion* next = r->next_in_collection_set();
2853     if (cl->doHeapRegion(r)) {
2854       cl->incomplete();
2855       return;
2856     }
2857     r = next;
2858   }
2859 }
2860 
2861 void G1CollectedHeap::collection_set_iterate_from(HeapRegion* r,
2862                                                   HeapRegionClosure *cl) {
2863   if (r == NULL) {
2864     // The CSet is empty so there's nothing to do.
2865     return;
2866   }
2867 
2868   assert(r->in_collection_set(),
2869          "Start region must be a member of the collection set.");
2870   HeapRegion* cur = r;
2871   while (cur != NULL) {
2872     HeapRegion* next = cur->next_in_collection_set();
2873     if (cl->doHeapRegion(cur) && false) {
2874       cl->incomplete();
2875       return;
2876     }
2877     cur = next;
2878   }
2879   cur = g1_policy()->collection_set();
2880   while (cur != r) {
2881     HeapRegion* next = cur->next_in_collection_set();
2882     if (cl->doHeapRegion(cur) && false) {
2883       cl->incomplete();
2884       return;
2885     }
2886     cur = next;
2887   }
2888 }
2889 
2890 HeapRegion* G1CollectedHeap::next_compaction_region(const HeapRegion* from) const {
2891   HeapRegion* result = _hrm.next_region_in_heap(from);
2892   while (result != NULL && result->is_pinned()) {
2893     result = _hrm.next_region_in_heap(result);
2894   }
2895   return result;
2896 }
2897 
2898 HeapWord* G1CollectedHeap::block_start(const void* addr) const {
2899   HeapRegion* hr = heap_region_containing(addr);
2900   return hr->block_start(addr);
2901 }
2902 
2903 size_t G1CollectedHeap::block_size(const HeapWord* addr) const {
2904   HeapRegion* hr = heap_region_containing(addr);
2905   return hr->block_size(addr);
2906 }
2907 
2908 bool G1CollectedHeap::block_is_obj(const HeapWord* addr) const {
2909   HeapRegion* hr = heap_region_containing(addr);
2910   return hr->block_is_obj(addr);
2911 }
2912 
2913 bool G1CollectedHeap::supports_tlab_allocation() const {
2914   return true;
2915 }
2916 
2917 size_t G1CollectedHeap::tlab_capacity(Thread* ignored) const {
2918   return (_g1_policy->young_list_target_length() - young_list()->survivor_length()) * HeapRegion::GrainBytes;
2919 }
2920 
2921 size_t G1CollectedHeap::tlab_used(Thread* ignored) const {
2922   return young_list()->eden_used_bytes();
2923 }
2924 
2925 // For G1 TLABs should not contain humongous objects, so the maximum TLAB size
2926 // must be equal to the humongous object limit.
2927 size_t G1CollectedHeap::max_tlab_size() const {
2928   return align_size_down(_humongous_object_threshold_in_words, MinObjAlignment);
2929 }
2930 
2931 size_t G1CollectedHeap::unsafe_max_tlab_alloc(Thread* ignored) const {
2932   AllocationContext_t context = AllocationContext::current();
2933   return _allocator->unsafe_max_tlab_alloc(context);
2934 }
2935 
2936 size_t G1CollectedHeap::max_capacity() const {
2937   return _hrm.reserved().byte_size();
2938 }
2939 
2940 jlong G1CollectedHeap::millis_since_last_gc() {
2941   // assert(false, "NYI");
2942   return 0;
2943 }
2944 
2945 void G1CollectedHeap::prepare_for_verify() {
2946   if (SafepointSynchronize::is_at_safepoint() || ! UseTLAB) {
2947     ensure_parsability(false);
2948   }
2949   g1_rem_set()->prepare_for_verify();
2950 }
2951 
2952 bool G1CollectedHeap::allocated_since_marking(oop obj, HeapRegion* hr,
2953                                               VerifyOption vo) {
2954   switch (vo) {
2955   case VerifyOption_G1UsePrevMarking:
2956     return hr->obj_allocated_since_prev_marking(obj);
2957   case VerifyOption_G1UseNextMarking:
2958     return hr->obj_allocated_since_next_marking(obj);
2959   case VerifyOption_G1UseMarkWord:
2960     return false;
2961   default:
2962     ShouldNotReachHere();
2963   }
2964   return false; // keep some compilers happy
2965 }
2966 
2967 HeapWord* G1CollectedHeap::top_at_mark_start(HeapRegion* hr, VerifyOption vo) {
2968   switch (vo) {
2969   case VerifyOption_G1UsePrevMarking: return hr->prev_top_at_mark_start();
2970   case VerifyOption_G1UseNextMarking: return hr->next_top_at_mark_start();
2971   case VerifyOption_G1UseMarkWord:    return NULL;
2972   default:                            ShouldNotReachHere();
2973   }
2974   return NULL; // keep some compilers happy
2975 }
2976 
2977 bool G1CollectedHeap::is_marked(oop obj, VerifyOption vo) {
2978   switch (vo) {
2979   case VerifyOption_G1UsePrevMarking: return isMarkedPrev(obj);
2980   case VerifyOption_G1UseNextMarking: return isMarkedNext(obj);
2981   case VerifyOption_G1UseMarkWord:    return obj->is_gc_marked();
2982   default:                            ShouldNotReachHere();
2983   }
2984   return false; // keep some compilers happy
2985 }
2986 
2987 const char* G1CollectedHeap::top_at_mark_start_str(VerifyOption vo) {
2988   switch (vo) {
2989   case VerifyOption_G1UsePrevMarking: return "PTAMS";
2990   case VerifyOption_G1UseNextMarking: return "NTAMS";
2991   case VerifyOption_G1UseMarkWord:    return "NONE";
2992   default:                            ShouldNotReachHere();
2993   }
2994   return NULL; // keep some compilers happy
2995 }
2996 
2997 class VerifyRootsClosure: public OopClosure {
2998 private:
2999   G1CollectedHeap* _g1h;
3000   VerifyOption     _vo;
3001   bool             _failures;
3002 public:
3003   // _vo == UsePrevMarking -> use "prev" marking information,
3004   // _vo == UseNextMarking -> use "next" marking information,
3005   // _vo == UseMarkWord    -> use mark word from object header.
3006   VerifyRootsClosure(VerifyOption vo) :
3007     _g1h(G1CollectedHeap::heap()),
3008     _vo(vo),
3009     _failures(false) { }
3010 
3011   bool failures() { return _failures; }
3012 
3013   template <class T> void do_oop_nv(T* p) {
3014     T heap_oop = oopDesc::load_heap_oop(p);
3015     if (!oopDesc::is_null(heap_oop)) {
3016       oop obj = oopDesc::decode_heap_oop_not_null(heap_oop);
3017       if (_g1h->is_obj_dead_cond(obj, _vo)) {
3018         gclog_or_tty->print_cr("Root location " PTR_FORMAT " "
3019                                "points to dead obj " PTR_FORMAT, p2i(p), p2i(obj));
3020         if (_vo == VerifyOption_G1UseMarkWord) {
3021           gclog_or_tty->print_cr("  Mark word: " INTPTR_FORMAT, (intptr_t)obj->mark());
3022         }
3023         obj->print_on(gclog_or_tty);
3024         _failures = true;
3025       }
3026     }
3027   }
3028 
3029   void do_oop(oop* p)       { do_oop_nv(p); }
3030   void do_oop(narrowOop* p) { do_oop_nv(p); }
3031 };
3032 
3033 class G1VerifyCodeRootOopClosure: public OopClosure {
3034   G1CollectedHeap* _g1h;
3035   OopClosure* _root_cl;
3036   nmethod* _nm;
3037   VerifyOption _vo;
3038   bool _failures;
3039 
3040   template <class T> void do_oop_work(T* p) {
3041     // First verify that this root is live
3042     _root_cl->do_oop(p);
3043 
3044     if (!G1VerifyHeapRegionCodeRoots) {
3045       // We're not verifying the code roots attached to heap region.
3046       return;
3047     }
3048 
3049     // Don't check the code roots during marking verification in a full GC
3050     if (_vo == VerifyOption_G1UseMarkWord) {
3051       return;
3052     }
3053 
3054     // Now verify that the current nmethod (which contains p) is
3055     // in the code root list of the heap region containing the
3056     // object referenced by p.
3057 
3058     T heap_oop = oopDesc::load_heap_oop(p);
3059     if (!oopDesc::is_null(heap_oop)) {
3060       oop obj = oopDesc::decode_heap_oop_not_null(heap_oop);
3061 
3062       // Now fetch the region containing the object
3063       HeapRegion* hr = _g1h->heap_region_containing(obj);
3064       HeapRegionRemSet* hrrs = hr->rem_set();
3065       // Verify that the strong code root list for this region
3066       // contains the nmethod
3067       if (!hrrs->strong_code_roots_list_contains(_nm)) {
3068         gclog_or_tty->print_cr("Code root location " PTR_FORMAT " "
3069                                "from nmethod " PTR_FORMAT " not in strong "
3070                                "code roots for region [" PTR_FORMAT "," PTR_FORMAT ")",
3071                                p2i(p), p2i(_nm), p2i(hr->bottom()), p2i(hr->end()));
3072         _failures = true;
3073       }
3074     }
3075   }
3076 
3077 public:
3078   G1VerifyCodeRootOopClosure(G1CollectedHeap* g1h, OopClosure* root_cl, VerifyOption vo):
3079     _g1h(g1h), _root_cl(root_cl), _vo(vo), _nm(NULL), _failures(false) {}
3080 
3081   void do_oop(oop* p) { do_oop_work(p); }
3082   void do_oop(narrowOop* p) { do_oop_work(p); }
3083 
3084   void set_nmethod(nmethod* nm) { _nm = nm; }
3085   bool failures() { return _failures; }
3086 };
3087 
3088 class G1VerifyCodeRootBlobClosure: public CodeBlobClosure {
3089   G1VerifyCodeRootOopClosure* _oop_cl;
3090 
3091 public:
3092   G1VerifyCodeRootBlobClosure(G1VerifyCodeRootOopClosure* oop_cl):
3093     _oop_cl(oop_cl) {}
3094 
3095   void do_code_blob(CodeBlob* cb) {
3096     nmethod* nm = cb->as_nmethod_or_null();
3097     if (nm != NULL) {
3098       _oop_cl->set_nmethod(nm);
3099       nm->oops_do(_oop_cl);
3100     }
3101   }
3102 };
3103 
3104 class YoungRefCounterClosure : public OopClosure {
3105   G1CollectedHeap* _g1h;
3106   int              _count;
3107  public:
3108   YoungRefCounterClosure(G1CollectedHeap* g1h) : _g1h(g1h), _count(0) {}
3109   void do_oop(oop* p)       { if (_g1h->is_in_young(*p)) { _count++; } }
3110   void do_oop(narrowOop* p) { ShouldNotReachHere(); }
3111 
3112   int count() { return _count; }
3113   void reset_count() { _count = 0; };
3114 };
3115 
3116 class VerifyKlassClosure: public KlassClosure {
3117   YoungRefCounterClosure _young_ref_counter_closure;
3118   OopClosure *_oop_closure;
3119  public:
3120   VerifyKlassClosure(G1CollectedHeap* g1h, OopClosure* cl) : _young_ref_counter_closure(g1h), _oop_closure(cl) {}
3121   void do_klass(Klass* k) {
3122     k->oops_do(_oop_closure);
3123 
3124     _young_ref_counter_closure.reset_count();
3125     k->oops_do(&_young_ref_counter_closure);
3126     if (_young_ref_counter_closure.count() > 0) {
3127       guarantee(k->has_modified_oops(), err_msg("Klass " PTR_FORMAT ", has young refs but is not dirty.", p2i(k)));
3128     }
3129   }
3130 };
3131 
3132 class VerifyLivenessOopClosure: public OopClosure {
3133   G1CollectedHeap* _g1h;
3134   VerifyOption _vo;
3135 public:
3136   VerifyLivenessOopClosure(G1CollectedHeap* g1h, VerifyOption vo):
3137     _g1h(g1h), _vo(vo)
3138   { }
3139   void do_oop(narrowOop *p) { do_oop_work(p); }
3140   void do_oop(      oop *p) { do_oop_work(p); }
3141 
3142   template <class T> void do_oop_work(T *p) {
3143     oop obj = oopDesc::load_decode_heap_oop(p);
3144     guarantee(obj == NULL || !_g1h->is_obj_dead_cond(obj, _vo),
3145               "Dead object referenced by a not dead object");
3146   }
3147 };
3148 
3149 class VerifyObjsInRegionClosure: public ObjectClosure {
3150 private:
3151   G1CollectedHeap* _g1h;
3152   size_t _live_bytes;
3153   HeapRegion *_hr;
3154   VerifyOption _vo;
3155 public:
3156   // _vo == UsePrevMarking -> use "prev" marking information,
3157   // _vo == UseNextMarking -> use "next" marking information,
3158   // _vo == UseMarkWord    -> use mark word from object header.
3159   VerifyObjsInRegionClosure(HeapRegion *hr, VerifyOption vo)
3160     : _live_bytes(0), _hr(hr), _vo(vo) {
3161     _g1h = G1CollectedHeap::heap();
3162   }
3163   void do_object(oop o) {
3164     VerifyLivenessOopClosure isLive(_g1h, _vo);
3165     assert(o != NULL, "Huh?");
3166     if (!_g1h->is_obj_dead_cond(o, _vo)) {
3167       // If the object is alive according to the mark word,
3168       // then verify that the marking information agrees.
3169       // Note we can't verify the contra-positive of the
3170       // above: if the object is dead (according to the mark
3171       // word), it may not be marked, or may have been marked
3172       // but has since became dead, or may have been allocated
3173       // since the last marking.
3174       if (_vo == VerifyOption_G1UseMarkWord) {
3175         guarantee(!_g1h->is_obj_dead(o), "mark word and concurrent mark mismatch");
3176       }
3177 
3178       o->oop_iterate_no_header(&isLive);
3179       if (!_hr->obj_allocated_since_prev_marking(o)) {
3180         size_t obj_size = o->size();    // Make sure we don't overflow
3181         _live_bytes += (obj_size * HeapWordSize);
3182       }
3183     }
3184   }
3185   size_t live_bytes() { return _live_bytes; }
3186 };
3187 
3188 class VerifyArchiveOopClosure: public OopClosure {
3189 public:
3190   VerifyArchiveOopClosure(HeapRegion *hr) { }
3191   void do_oop(narrowOop *p) { do_oop_work(p); }
3192   void do_oop(      oop *p) { do_oop_work(p); }
3193 
3194   template <class T> void do_oop_work(T *p) {
3195     oop obj = oopDesc::load_decode_heap_oop(p);
3196     guarantee(obj == NULL || G1MarkSweep::in_archive_range(obj),
3197               err_msg("Archive object at " PTR_FORMAT " references a non-archive object at " PTR_FORMAT,
3198                       p2i(p), p2i(obj)));
3199   }
3200 };
3201 
3202 class VerifyArchiveRegionClosure: public ObjectClosure {
3203 public:
3204   VerifyArchiveRegionClosure(HeapRegion *hr) { }
3205   // Verify that all object pointers are to archive regions.
3206   void do_object(oop o) {
3207     VerifyArchiveOopClosure checkOop(NULL);
3208     assert(o != NULL, "Should not be here for NULL oops");
3209     o->oop_iterate_no_header(&checkOop);
3210   }
3211 };
3212 
3213 class VerifyRegionClosure: public HeapRegionClosure {
3214 private:
3215   bool             _par;
3216   VerifyOption     _vo;
3217   bool             _failures;
3218 public:
3219   // _vo == UsePrevMarking -> use "prev" marking information,
3220   // _vo == UseNextMarking -> use "next" marking information,
3221   // _vo == UseMarkWord    -> use mark word from object header.
3222   VerifyRegionClosure(bool par, VerifyOption vo)
3223     : _par(par),
3224       _vo(vo),
3225       _failures(false) {}
3226 
3227   bool failures() {
3228     return _failures;
3229   }
3230 
3231   bool doHeapRegion(HeapRegion* r) {
3232     // For archive regions, verify there are no heap pointers to
3233     // non-pinned regions. For all others, verify liveness info.
3234     if (r->is_archive()) {
3235       VerifyArchiveRegionClosure verify_oop_pointers(r);
3236       r->object_iterate(&verify_oop_pointers);
3237       return true;
3238     }
3239     if (!r->is_continues_humongous()) {
3240       bool failures = false;
3241       r->verify(_vo, &failures);
3242       if (failures) {
3243         _failures = true;
3244       } else {
3245         VerifyObjsInRegionClosure not_dead_yet_cl(r, _vo);
3246         r->object_iterate(&not_dead_yet_cl);
3247         if (_vo != VerifyOption_G1UseNextMarking) {
3248           if (r->max_live_bytes() < not_dead_yet_cl.live_bytes()) {
3249             gclog_or_tty->print_cr("[" PTR_FORMAT "," PTR_FORMAT "] "
3250                                    "max_live_bytes " SIZE_FORMAT " "
3251                                    "< calculated " SIZE_FORMAT,
3252                                    p2i(r->bottom()), p2i(r->end()),
3253                                    r->max_live_bytes(),
3254                                  not_dead_yet_cl.live_bytes());
3255             _failures = true;
3256           }
3257         } else {
3258           // When vo == UseNextMarking we cannot currently do a sanity
3259           // check on the live bytes as the calculation has not been
3260           // finalized yet.
3261         }
3262       }
3263     }
3264     return false; // stop the region iteration if we hit a failure
3265   }
3266 };
3267 
3268 // This is the task used for parallel verification of the heap regions
3269 
3270 class G1ParVerifyTask: public AbstractGangTask {
3271 private:
3272   G1CollectedHeap*  _g1h;
3273   VerifyOption      _vo;
3274   bool              _failures;
3275   HeapRegionClaimer _hrclaimer;
3276 
3277 public:
3278   // _vo == UsePrevMarking -> use "prev" marking information,
3279   // _vo == UseNextMarking -> use "next" marking information,
3280   // _vo == UseMarkWord    -> use mark word from object header.
3281   G1ParVerifyTask(G1CollectedHeap* g1h, VerifyOption vo) :
3282       AbstractGangTask("Parallel verify task"),
3283       _g1h(g1h),
3284       _vo(vo),
3285       _failures(false),
3286       _hrclaimer(g1h->workers()->active_workers()) {}
3287 
3288   bool failures() {
3289     return _failures;
3290   }
3291 
3292   void work(uint worker_id) {
3293     HandleMark hm;
3294     VerifyRegionClosure blk(true, _vo);
3295     _g1h->heap_region_par_iterate(&blk, worker_id, &_hrclaimer);
3296     if (blk.failures()) {
3297       _failures = true;
3298     }
3299   }
3300 };
3301 
3302 void G1CollectedHeap::verify(bool silent, VerifyOption vo) {
3303   if (SafepointSynchronize::is_at_safepoint()) {
3304     assert(Thread::current()->is_VM_thread(),
3305            "Expected to be executed serially by the VM thread at this point");
3306 
3307     if (!silent) { gclog_or_tty->print("Roots "); }
3308     VerifyRootsClosure rootsCl(vo);
3309     VerifyKlassClosure klassCl(this, &rootsCl);
3310     CLDToKlassAndOopClosure cldCl(&klassCl, &rootsCl, false);
3311 
3312     // We apply the relevant closures to all the oops in the
3313     // system dictionary, class loader data graph, the string table
3314     // and the nmethods in the code cache.
3315     G1VerifyCodeRootOopClosure codeRootsCl(this, &rootsCl, vo);
3316     G1VerifyCodeRootBlobClosure blobsCl(&codeRootsCl);
3317 
3318     {
3319       G1RootProcessor root_processor(this, 1);
3320       root_processor.process_all_roots(&rootsCl,
3321                                        &cldCl,
3322                                        &blobsCl);
3323     }
3324 
3325     bool failures = rootsCl.failures() || codeRootsCl.failures();
3326 
3327     if (vo != VerifyOption_G1UseMarkWord) {
3328       // If we're verifying during a full GC then the region sets
3329       // will have been torn down at the start of the GC. Therefore
3330       // verifying the region sets will fail. So we only verify
3331       // the region sets when not in a full GC.
3332       if (!silent) { gclog_or_tty->print("HeapRegionSets "); }
3333       verify_region_sets();
3334     }
3335 
3336     if (!silent) { gclog_or_tty->print("HeapRegions "); }
3337     if (GCParallelVerificationEnabled && ParallelGCThreads > 1) {
3338 
3339       G1ParVerifyTask task(this, vo);
3340       workers()->run_task(&task);
3341       if (task.failures()) {
3342         failures = true;
3343       }
3344 
3345     } else {
3346       VerifyRegionClosure blk(false, vo);
3347       heap_region_iterate(&blk);
3348       if (blk.failures()) {
3349         failures = true;
3350       }
3351     }
3352 
3353     if (G1StringDedup::is_enabled()) {
3354       if (!silent) gclog_or_tty->print("StrDedup ");
3355       G1StringDedup::verify();
3356     }
3357 
3358     if (failures) {
3359       gclog_or_tty->print_cr("Heap:");
3360       // It helps to have the per-region information in the output to
3361       // help us track down what went wrong. This is why we call
3362       // print_extended_on() instead of print_on().
3363       print_extended_on(gclog_or_tty);
3364       gclog_or_tty->cr();
3365       gclog_or_tty->flush();
3366     }
3367     guarantee(!failures, "there should not have been any failures");
3368   } else {
3369     if (!silent) {
3370       gclog_or_tty->print("(SKIPPING Roots, HeapRegionSets, HeapRegions, RemSet");
3371       if (G1StringDedup::is_enabled()) {
3372         gclog_or_tty->print(", StrDedup");
3373       }
3374       gclog_or_tty->print(") ");
3375     }
3376   }
3377 }
3378 
3379 void G1CollectedHeap::verify(bool silent) {
3380   verify(silent, VerifyOption_G1UsePrevMarking);
3381 }
3382 
3383 double G1CollectedHeap::verify(bool guard, const char* msg) {
3384   double verify_time_ms = 0.0;
3385 
3386   if (guard && total_collections() >= VerifyGCStartAt) {
3387     double verify_start = os::elapsedTime();
3388     HandleMark hm;  // Discard invalid handles created during verification
3389     prepare_for_verify();
3390     Universe::verify(VerifyOption_G1UsePrevMarking, msg);
3391     verify_time_ms = (os::elapsedTime() - verify_start) * 1000;
3392   }
3393 
3394   return verify_time_ms;
3395 }
3396 
3397 void G1CollectedHeap::verify_before_gc() {
3398   double verify_time_ms = verify(VerifyBeforeGC, " VerifyBeforeGC:");
3399   g1_policy()->phase_times()->record_verify_before_time_ms(verify_time_ms);
3400 }
3401 
3402 void G1CollectedHeap::verify_after_gc() {
3403   double verify_time_ms = verify(VerifyAfterGC, " VerifyAfterGC:");
3404   g1_policy()->phase_times()->record_verify_after_time_ms(verify_time_ms);
3405 }
3406 
3407 class PrintRegionClosure: public HeapRegionClosure {
3408   outputStream* _st;
3409 public:
3410   PrintRegionClosure(outputStream* st) : _st(st) {}
3411   bool doHeapRegion(HeapRegion* r) {
3412     r->print_on(_st);
3413     return false;
3414   }
3415 };
3416 
3417 bool G1CollectedHeap::is_obj_dead_cond(const oop obj,
3418                                        const HeapRegion* hr,
3419                                        const VerifyOption vo) const {
3420   switch (vo) {
3421   case VerifyOption_G1UsePrevMarking: return is_obj_dead(obj, hr);
3422   case VerifyOption_G1UseNextMarking: return is_obj_ill(obj, hr);
3423   case VerifyOption_G1UseMarkWord:    return !obj->is_gc_marked() && !hr->is_archive();
3424   default:                            ShouldNotReachHere();
3425   }
3426   return false; // keep some compilers happy
3427 }
3428 
3429 bool G1CollectedHeap::is_obj_dead_cond(const oop obj,
3430                                        const VerifyOption vo) const {
3431   switch (vo) {
3432   case VerifyOption_G1UsePrevMarking: return is_obj_dead(obj);
3433   case VerifyOption_G1UseNextMarking: return is_obj_ill(obj);
3434   case VerifyOption_G1UseMarkWord: {
3435     HeapRegion* hr = _hrm.addr_to_region((HeapWord*)obj);
3436     return !obj->is_gc_marked() && !hr->is_archive();
3437   }
3438   default:                            ShouldNotReachHere();
3439   }
3440   return false; // keep some compilers happy
3441 }
3442 
3443 void G1CollectedHeap::print_on(outputStream* st) const {
3444   st->print(" %-20s", "garbage-first heap");
3445   st->print(" total " SIZE_FORMAT "K, used " SIZE_FORMAT "K",
3446             capacity()/K, used_unlocked()/K);
3447   st->print(" [" PTR_FORMAT ", " PTR_FORMAT ", " PTR_FORMAT ")",
3448             p2i(_hrm.reserved().start()),
3449             p2i(_hrm.reserved().start() + _hrm.length() + HeapRegion::GrainWords),
3450             p2i(_hrm.reserved().end()));
3451   st->cr();
3452   st->print("  region size " SIZE_FORMAT "K, ", HeapRegion::GrainBytes / K);
3453   uint young_regions = _young_list->length();
3454   st->print("%u young (" SIZE_FORMAT "K), ", young_regions,
3455             (size_t) young_regions * HeapRegion::GrainBytes / K);
3456   uint survivor_regions = g1_policy()->recorded_survivor_regions();
3457   st->print("%u survivors (" SIZE_FORMAT "K)", survivor_regions,
3458             (size_t) survivor_regions * HeapRegion::GrainBytes / K);
3459   st->cr();
3460   MetaspaceAux::print_on(st);
3461 }
3462 
3463 void G1CollectedHeap::print_extended_on(outputStream* st) const {
3464   print_on(st);
3465 
3466   // Print the per-region information.
3467   st->cr();
3468   st->print_cr("Heap Regions: (E=young(eden), S=young(survivor), O=old, "
3469                "HS=humongous(starts), HC=humongous(continues), "
3470                "CS=collection set, F=free, A=archive, TS=gc time stamp, "
3471                "PTAMS=previous top-at-mark-start, "
3472                "NTAMS=next top-at-mark-start)");
3473   PrintRegionClosure blk(st);
3474   heap_region_iterate(&blk);
3475 }
3476 
3477 void G1CollectedHeap::print_on_error(outputStream* st) const {
3478   this->CollectedHeap::print_on_error(st);
3479 
3480   if (_cm != NULL) {
3481     st->cr();
3482     _cm->print_on_error(st);
3483   }
3484 }
3485 
3486 void G1CollectedHeap::print_gc_threads_on(outputStream* st) const {
3487   workers()->print_worker_threads_on(st);
3488   _cmThread->print_on(st);
3489   st->cr();
3490   _cm->print_worker_threads_on(st);
3491   _cg1r->print_worker_threads_on(st);
3492   if (G1StringDedup::is_enabled()) {
3493     G1StringDedup::print_worker_threads_on(st);
3494   }
3495 }
3496 
3497 void G1CollectedHeap::gc_threads_do(ThreadClosure* tc) const {
3498   workers()->threads_do(tc);
3499   tc->do_thread(_cmThread);
3500   _cg1r->threads_do(tc);
3501   if (G1StringDedup::is_enabled()) {
3502     G1StringDedup::threads_do(tc);
3503   }
3504 }
3505 
3506 void G1CollectedHeap::print_tracing_info() const {
3507   // We'll overload this to mean "trace GC pause statistics."
3508   if (TraceYoungGenTime || TraceOldGenTime) {
3509     // The "G1CollectorPolicy" is keeping track of these stats, so delegate
3510     // to that.
3511     g1_policy()->print_tracing_info();
3512   }
3513   if (G1SummarizeRSetStats) {
3514     g1_rem_set()->print_summary_info();
3515   }
3516   if (G1SummarizeConcMark) {
3517     concurrent_mark()->print_summary_info();
3518   }
3519   g1_policy()->print_yg_surv_rate_info();
3520 }
3521 
3522 #ifndef PRODUCT
3523 // Helpful for debugging RSet issues.
3524 
3525 class PrintRSetsClosure : public HeapRegionClosure {
3526 private:
3527   const char* _msg;
3528   size_t _occupied_sum;
3529 
3530 public:
3531   bool doHeapRegion(HeapRegion* r) {
3532     HeapRegionRemSet* hrrs = r->rem_set();
3533     size_t occupied = hrrs->occupied();
3534     _occupied_sum += occupied;
3535 
3536     gclog_or_tty->print_cr("Printing RSet for region " HR_FORMAT,
3537                            HR_FORMAT_PARAMS(r));
3538     if (occupied == 0) {
3539       gclog_or_tty->print_cr("  RSet is empty");
3540     } else {
3541       hrrs->print();
3542     }
3543     gclog_or_tty->print_cr("----------");
3544     return false;
3545   }
3546 
3547   PrintRSetsClosure(const char* msg) : _msg(msg), _occupied_sum(0) {
3548     gclog_or_tty->cr();
3549     gclog_or_tty->print_cr("========================================");
3550     gclog_or_tty->print_cr("%s", msg);
3551     gclog_or_tty->cr();
3552   }
3553 
3554   ~PrintRSetsClosure() {
3555     gclog_or_tty->print_cr("Occupied Sum: " SIZE_FORMAT, _occupied_sum);
3556     gclog_or_tty->print_cr("========================================");
3557     gclog_or_tty->cr();
3558   }
3559 };
3560 
3561 void G1CollectedHeap::print_cset_rsets() {
3562   PrintRSetsClosure cl("Printing CSet RSets");
3563   collection_set_iterate(&cl);
3564 }
3565 
3566 void G1CollectedHeap::print_all_rsets() {
3567   PrintRSetsClosure cl("Printing All RSets");;
3568   heap_region_iterate(&cl);
3569 }
3570 #endif // PRODUCT
3571 
3572 G1HeapSummary G1CollectedHeap::create_g1_heap_summary() {
3573   YoungList* young_list = heap()->young_list();
3574 
3575   size_t eden_used_bytes = young_list->eden_used_bytes();
3576   size_t survivor_used_bytes = young_list->survivor_used_bytes();
3577 
3578   size_t eden_capacity_bytes =
3579     (g1_policy()->young_list_target_length() * HeapRegion::GrainBytes) - survivor_used_bytes;
3580 
3581   VirtualSpaceSummary heap_summary = create_heap_space_summary();
3582   return G1HeapSummary(heap_summary, used(), eden_used_bytes, eden_capacity_bytes, survivor_used_bytes);
3583 }
3584 
3585 G1EvacSummary G1CollectedHeap::create_g1_evac_summary(G1EvacStats* stats) {
3586   return G1EvacSummary(stats->allocated(), stats->wasted(), stats->undo_wasted(),
3587                        stats->unused(), stats->used(), stats->region_end_waste(),
3588                        stats->regions_filled(), stats->direct_allocated(),
3589                        stats->failure_used(), stats->failure_waste());
3590 }
3591 
3592 void G1CollectedHeap::trace_heap(GCWhen::Type when, const GCTracer* gc_tracer) {
3593   const G1HeapSummary& heap_summary = create_g1_heap_summary();
3594   gc_tracer->report_gc_heap_summary(when, heap_summary);
3595 
3596   const MetaspaceSummary& metaspace_summary = create_metaspace_summary();
3597   gc_tracer->report_metaspace_summary(when, metaspace_summary);
3598 }
3599 
3600 
3601 G1CollectedHeap* G1CollectedHeap::heap() {
3602   CollectedHeap* heap = Universe::heap();
3603   assert(heap != NULL, "Uninitialized access to G1CollectedHeap::heap()");
3604   assert(heap->kind() == CollectedHeap::G1CollectedHeap, "Not a G1CollectedHeap");
3605   return (G1CollectedHeap*)heap;
3606 }
3607 
3608 void G1CollectedHeap::gc_prologue(bool full /* Ignored */) {
3609   // always_do_update_barrier = false;
3610   assert(InlineCacheBuffer::is_empty(), "should have cleaned up ICBuffer");
3611   // Fill TLAB's and such
3612   accumulate_statistics_all_tlabs();
3613   ensure_parsability(true);
3614 
3615   if (G1SummarizeRSetStats && (G1SummarizeRSetStatsPeriod > 0) &&
3616       (total_collections() % G1SummarizeRSetStatsPeriod == 0)) {
3617     g1_rem_set()->print_periodic_summary_info("Before GC RS summary");
3618   }
3619 }
3620 
3621 void G1CollectedHeap::gc_epilogue(bool full) {
3622 
3623   if (G1SummarizeRSetStats &&
3624       (G1SummarizeRSetStatsPeriod > 0) &&
3625       // we are at the end of the GC. Total collections has already been increased.
3626       ((total_collections() - 1) % G1SummarizeRSetStatsPeriod == 0)) {
3627     g1_rem_set()->print_periodic_summary_info("After GC RS summary");
3628   }
3629 
3630   // FIXME: what is this about?
3631   // I'm ignoring the "fill_newgen()" call if "alloc_event_enabled"
3632   // is set.
3633   COMPILER2_PRESENT(assert(DerivedPointerTable::is_empty(),
3634                         "derived pointer present"));

3635   // always_do_update_barrier = true;
3636 
3637   resize_all_tlabs();
3638   allocation_context_stats().update(full);
3639 
3640   // We have just completed a GC. Update the soft reference
3641   // policy with the new heap occupancy
3642   Universe::update_heap_info_at_gc();
3643 }
3644 
3645 HeapWord* G1CollectedHeap::do_collection_pause(size_t word_size,
3646                                                uint gc_count_before,
3647                                                bool* succeeded,
3648                                                GCCause::Cause gc_cause) {
3649   assert_heap_not_locked_and_not_at_safepoint();
3650   g1_policy()->record_stop_world_start();
3651   VM_G1IncCollectionPause op(gc_count_before,
3652                              word_size,
3653                              false, /* should_initiate_conc_mark */
3654                              g1_policy()->max_pause_time_ms(),
3655                              gc_cause);
3656 
3657   op.set_allocation_context(AllocationContext::current());
3658   VMThread::execute(&op);
3659 
3660   HeapWord* result = op.result();
3661   bool ret_succeeded = op.prologue_succeeded() && op.pause_succeeded();
3662   assert(result == NULL || ret_succeeded,
3663          "the result should be NULL if the VM did not succeed");
3664   *succeeded = ret_succeeded;
3665 
3666   assert_heap_not_locked();
3667   return result;
3668 }
3669 
3670 void
3671 G1CollectedHeap::doConcurrentMark() {
3672   MutexLockerEx x(CGC_lock, Mutex::_no_safepoint_check_flag);
3673   if (!_cmThread->in_progress()) {
3674     _cmThread->set_started();
3675     CGC_lock->notify();
3676   }
3677 }
3678 
3679 size_t G1CollectedHeap::pending_card_num() {
3680   size_t extra_cards = 0;
3681   JavaThread *curr = Threads::first();
3682   while (curr != NULL) {
3683     DirtyCardQueue& dcq = curr->dirty_card_queue();
3684     extra_cards += dcq.size();
3685     curr = curr->next();
3686   }
3687   DirtyCardQueueSet& dcqs = JavaThread::dirty_card_queue_set();
3688   size_t buffer_size = dcqs.buffer_size();
3689   size_t buffer_num = dcqs.completed_buffers_num();
3690 
3691   // PtrQueueSet::buffer_size() and PtrQueue:size() return sizes
3692   // in bytes - not the number of 'entries'. We need to convert
3693   // into a number of cards.
3694   return (buffer_size * buffer_num + extra_cards) / oopSize;
3695 }
3696 
3697 class RegisterHumongousWithInCSetFastTestClosure : public HeapRegionClosure {
3698  private:
3699   size_t _total_humongous;
3700   size_t _candidate_humongous;
3701 
3702   DirtyCardQueue _dcq;
3703 
3704   // We don't nominate objects with many remembered set entries, on
3705   // the assumption that such objects are likely still live.
3706   bool is_remset_small(HeapRegion* region) const {
3707     HeapRegionRemSet* const rset = region->rem_set();
3708     return G1EagerReclaimHumongousObjectsWithStaleRefs
3709       ? rset->occupancy_less_or_equal_than(G1RSetSparseRegionEntries)
3710       : rset->is_empty();
3711   }
3712 
3713   bool is_typeArray_region(HeapRegion* region) const {
3714     return oop(region->bottom())->is_typeArray();
3715   }
3716 
3717   bool humongous_region_is_candidate(G1CollectedHeap* heap, HeapRegion* region) const {
3718     assert(region->is_starts_humongous(), "Must start a humongous object");
3719 
3720     // Candidate selection must satisfy the following constraints
3721     // while concurrent marking is in progress:
3722     //
3723     // * In order to maintain SATB invariants, an object must not be
3724     // reclaimed if it was allocated before the start of marking and
3725     // has not had its references scanned.  Such an object must have
3726     // its references (including type metadata) scanned to ensure no
3727     // live objects are missed by the marking process.  Objects
3728     // allocated after the start of concurrent marking don't need to
3729     // be scanned.
3730     //
3731     // * An object must not be reclaimed if it is on the concurrent
3732     // mark stack.  Objects allocated after the start of concurrent
3733     // marking are never pushed on the mark stack.
3734     //
3735     // Nominating only objects allocated after the start of concurrent
3736     // marking is sufficient to meet both constraints.  This may miss
3737     // some objects that satisfy the constraints, but the marking data
3738     // structures don't support efficiently performing the needed
3739     // additional tests or scrubbing of the mark stack.
3740     //
3741     // However, we presently only nominate is_typeArray() objects.
3742     // A humongous object containing references induces remembered
3743     // set entries on other regions.  In order to reclaim such an
3744     // object, those remembered sets would need to be cleaned up.
3745     //
3746     // We also treat is_typeArray() objects specially, allowing them
3747     // to be reclaimed even if allocated before the start of
3748     // concurrent mark.  For this we rely on mark stack insertion to
3749     // exclude is_typeArray() objects, preventing reclaiming an object
3750     // that is in the mark stack.  We also rely on the metadata for
3751     // such objects to be built-in and so ensured to be kept live.
3752     // Frequent allocation and drop of large binary blobs is an
3753     // important use case for eager reclaim, and this special handling
3754     // may reduce needed headroom.
3755 
3756     return is_typeArray_region(region) && is_remset_small(region);
3757   }
3758 
3759  public:
3760   RegisterHumongousWithInCSetFastTestClosure()
3761   : _total_humongous(0),
3762     _candidate_humongous(0),
3763     _dcq(&JavaThread::dirty_card_queue_set()) {
3764   }
3765 
3766   virtual bool doHeapRegion(HeapRegion* r) {
3767     if (!r->is_starts_humongous()) {
3768       return false;
3769     }
3770     G1CollectedHeap* g1h = G1CollectedHeap::heap();
3771 
3772     bool is_candidate = humongous_region_is_candidate(g1h, r);
3773     uint rindex = r->hrm_index();
3774     g1h->set_humongous_reclaim_candidate(rindex, is_candidate);
3775     if (is_candidate) {
3776       _candidate_humongous++;
3777       g1h->register_humongous_region_with_cset(rindex);
3778       // Is_candidate already filters out humongous object with large remembered sets.
3779       // If we have a humongous object with a few remembered sets, we simply flush these
3780       // remembered set entries into the DCQS. That will result in automatic
3781       // re-evaluation of their remembered set entries during the following evacuation
3782       // phase.
3783       if (!r->rem_set()->is_empty()) {
3784         guarantee(r->rem_set()->occupancy_less_or_equal_than(G1RSetSparseRegionEntries),
3785                   "Found a not-small remembered set here. This is inconsistent with previous assumptions.");
3786         G1SATBCardTableLoggingModRefBS* bs = g1h->g1_barrier_set();
3787         HeapRegionRemSetIterator hrrs(r->rem_set());
3788         size_t card_index;
3789         while (hrrs.has_next(card_index)) {
3790           jbyte* card_ptr = (jbyte*)bs->byte_for_index(card_index);
3791           // The remembered set might contain references to already freed
3792           // regions. Filter out such entries to avoid failing card table
3793           // verification.
3794           if (!g1h->heap_region_containing(bs->addr_for(card_ptr))->is_free()) {
3795             if (*card_ptr != CardTableModRefBS::dirty_card_val()) {
3796               *card_ptr = CardTableModRefBS::dirty_card_val();
3797               _dcq.enqueue(card_ptr);
3798             }
3799           }
3800         }
3801         r->rem_set()->clear_locked();
3802       }
3803       assert(r->rem_set()->is_empty(), "At this point any humongous candidate remembered set must be empty.");
3804     }
3805     _total_humongous++;
3806 
3807     return false;
3808   }
3809 
3810   size_t total_humongous() const { return _total_humongous; }
3811   size_t candidate_humongous() const { return _candidate_humongous; }
3812 
3813   void flush_rem_set_entries() { _dcq.flush(); }
3814 };
3815 
3816 void G1CollectedHeap::register_humongous_regions_with_cset() {
3817   if (!G1EagerReclaimHumongousObjects) {
3818     g1_policy()->phase_times()->record_fast_reclaim_humongous_stats(0.0, 0, 0);
3819     return;
3820   }
3821   double time = os::elapsed_counter();
3822 
3823   // Collect reclaim candidate information and register candidates with cset.
3824   RegisterHumongousWithInCSetFastTestClosure cl;
3825   heap_region_iterate(&cl);
3826 
3827   time = ((double)(os::elapsed_counter() - time) / os::elapsed_frequency()) * 1000.0;
3828   g1_policy()->phase_times()->record_fast_reclaim_humongous_stats(time,
3829                                                                   cl.total_humongous(),
3830                                                                   cl.candidate_humongous());
3831   _has_humongous_reclaim_candidates = cl.candidate_humongous() > 0;
3832 
3833   // Finally flush all remembered set entries to re-check into the global DCQS.
3834   cl.flush_rem_set_entries();
3835 }
3836 
3837 #ifdef ASSERT
3838 class VerifyCSetClosure: public HeapRegionClosure {
3839 public:
3840   bool doHeapRegion(HeapRegion* hr) {
3841     // Here we check that the CSet region's RSet is ready for parallel
3842     // iteration. The fields that we'll verify are only manipulated
3843     // when the region is part of a CSet and is collected. Afterwards,
3844     // we reset these fields when we clear the region's RSet (when the
3845     // region is freed) so they are ready when the region is
3846     // re-allocated. The only exception to this is if there's an
3847     // evacuation failure and instead of freeing the region we leave
3848     // it in the heap. In that case, we reset these fields during
3849     // evacuation failure handling.
3850     guarantee(hr->rem_set()->verify_ready_for_par_iteration(), "verification");
3851 
3852     // Here's a good place to add any other checks we'd like to
3853     // perform on CSet regions.
3854     return false;
3855   }
3856 };
3857 #endif // ASSERT
3858 
3859 uint G1CollectedHeap::num_task_queues() const {
3860   return _task_queues->size();
3861 }
3862 
3863 #if TASKQUEUE_STATS
3864 void G1CollectedHeap::print_taskqueue_stats_hdr(outputStream* const st) {
3865   st->print_raw_cr("GC Task Stats");
3866   st->print_raw("thr "); TaskQueueStats::print_header(1, st); st->cr();
3867   st->print_raw("--- "); TaskQueueStats::print_header(2, st); st->cr();
3868 }
3869 
3870 void G1CollectedHeap::print_taskqueue_stats(outputStream* const st) const {
3871   print_taskqueue_stats_hdr(st);
3872 
3873   TaskQueueStats totals;
3874   const uint n = num_task_queues();
3875   for (uint i = 0; i < n; ++i) {
3876     st->print("%3u ", i); task_queue(i)->stats.print(st); st->cr();
3877     totals += task_queue(i)->stats;
3878   }
3879   st->print_raw("tot "); totals.print(st); st->cr();
3880 
3881   DEBUG_ONLY(totals.verify());
3882 }
3883 
3884 void G1CollectedHeap::reset_taskqueue_stats() {
3885   const uint n = num_task_queues();
3886   for (uint i = 0; i < n; ++i) {
3887     task_queue(i)->stats.reset();
3888   }
3889 }
3890 #endif // TASKQUEUE_STATS
3891 
3892 void G1CollectedHeap::log_gc_header() {
3893   if (!G1Log::fine()) {
3894     return;
3895   }
3896 
3897   gclog_or_tty->gclog_stamp(_gc_tracer_stw->gc_id());
3898 
3899   GCCauseString gc_cause_str = GCCauseString("GC pause", gc_cause())
3900     .append(collector_state()->gcs_are_young() ? "(young)" : "(mixed)")
3901     .append(collector_state()->during_initial_mark_pause() ? " (initial-mark)" : "");
3902 
3903   gclog_or_tty->print("[%s", (const char*)gc_cause_str);
3904 }
3905 
3906 void G1CollectedHeap::log_gc_footer(double pause_time_sec) {
3907   if (!G1Log::fine()) {
3908     return;
3909   }
3910 
3911   if (G1Log::finer()) {
3912     if (evacuation_failed()) {
3913       gclog_or_tty->print(" (to-space exhausted)");
3914     }
3915     gclog_or_tty->print_cr(", %3.7f secs]", pause_time_sec);
3916     g1_policy()->phase_times()->note_gc_end();
3917     g1_policy()->phase_times()->print(pause_time_sec);
3918     g1_policy()->print_detailed_heap_transition();
3919   } else {
3920     if (evacuation_failed()) {
3921       gclog_or_tty->print("--");
3922     }
3923     g1_policy()->print_heap_transition();
3924     gclog_or_tty->print_cr(", %3.7f secs]", pause_time_sec);
3925   }
3926   gclog_or_tty->flush();
3927 }
3928 
3929 void G1CollectedHeap::wait_for_root_region_scanning() {
3930   double scan_wait_start = os::elapsedTime();
3931   // We have to wait until the CM threads finish scanning the
3932   // root regions as it's the only way to ensure that all the
3933   // objects on them have been correctly scanned before we start
3934   // moving them during the GC.
3935   bool waited = _cm->root_regions()->wait_until_scan_finished();
3936   double wait_time_ms = 0.0;
3937   if (waited) {
3938     double scan_wait_end = os::elapsedTime();
3939     wait_time_ms = (scan_wait_end - scan_wait_start) * 1000.0;
3940   }
3941   g1_policy()->phase_times()->record_root_region_scan_wait_time(wait_time_ms);
3942 }
3943 
3944 bool
3945 G1CollectedHeap::do_collection_pause_at_safepoint(double target_pause_time_ms) {
3946   assert_at_safepoint(true /* should_be_vm_thread */);
3947   guarantee(!is_gc_active(), "collection is not reentrant");
3948 
3949   if (GC_locker::check_active_before_gc()) {
3950     return false;
3951   }
3952 
3953   _gc_timer_stw->register_gc_start();
3954 
3955   _gc_tracer_stw->report_gc_start(gc_cause(), _gc_timer_stw->gc_start());
3956 
3957   SvcGCMarker sgcm(SvcGCMarker::MINOR);
3958   ResourceMark rm;
3959 
3960   wait_for_root_region_scanning();
3961 
3962   G1Log::update_level();
3963   print_heap_before_gc();
3964   trace_heap_before_gc(_gc_tracer_stw);
3965 
3966   verify_region_sets_optional();
3967   verify_dirty_young_regions();
3968 
3969   // This call will decide whether this pause is an initial-mark
3970   // pause. If it is, during_initial_mark_pause() will return true
3971   // for the duration of this pause.
3972   g1_policy()->decide_on_conc_mark_initiation();
3973 
3974   // We do not allow initial-mark to be piggy-backed on a mixed GC.
3975   assert(!collector_state()->during_initial_mark_pause() ||
3976           collector_state()->gcs_are_young(), "sanity");
3977 
3978   // We also do not allow mixed GCs during marking.
3979   assert(!collector_state()->mark_in_progress() || collector_state()->gcs_are_young(), "sanity");
3980 
3981   // Record whether this pause is an initial mark. When the current
3982   // thread has completed its logging output and it's safe to signal
3983   // the CM thread, the flag's value in the policy has been reset.
3984   bool should_start_conc_mark = collector_state()->during_initial_mark_pause();
3985 
3986   // Inner scope for scope based logging, timers, and stats collection
3987   {
3988     EvacuationInfo evacuation_info;
3989 
3990     if (collector_state()->during_initial_mark_pause()) {
3991       // We are about to start a marking cycle, so we increment the
3992       // full collection counter.
3993       increment_old_marking_cycles_started();
3994       register_concurrent_cycle_start(_gc_timer_stw->gc_start());
3995     }
3996 
3997     _gc_tracer_stw->report_yc_type(collector_state()->yc_type());
3998 
3999     TraceCPUTime tcpu(G1Log::finer(), true, gclog_or_tty);
4000 
4001     uint active_workers = AdaptiveSizePolicy::calc_active_workers(workers()->total_workers(),
4002                                                                   workers()->active_workers(),
4003                                                                   Threads::number_of_non_daemon_threads());
4004     workers()->set_active_workers(active_workers);
4005 
4006     double pause_start_sec = os::elapsedTime();
4007     g1_policy()->phase_times()->note_gc_start(active_workers, collector_state()->mark_in_progress());
4008     log_gc_header();
4009 
4010     TraceCollectorStats tcs(g1mm()->incremental_collection_counters());
4011     TraceMemoryManagerStats tms(false /* fullGC */, gc_cause());
4012 
4013     // If the secondary_free_list is not empty, append it to the
4014     // free_list. No need to wait for the cleanup operation to finish;
4015     // the region allocation code will check the secondary_free_list
4016     // and wait if necessary. If the G1StressConcRegionFreeing flag is
4017     // set, skip this step so that the region allocation code has to
4018     // get entries from the secondary_free_list.
4019     if (!G1StressConcRegionFreeing) {
4020       append_secondary_free_list_if_not_empty_with_lock();
4021     }
4022 
4023     assert(check_young_list_well_formed(), "young list should be well formed");
4024 
4025     // Don't dynamically change the number of GC threads this early.  A value of
4026     // 0 is used to indicate serial work.  When parallel work is done,
4027     // it will be set.
4028 
4029     { // Call to jvmpi::post_class_unload_events must occur outside of active GC
4030       IsGCActiveMark x;
4031 
4032       gc_prologue(false);
4033       increment_total_collections(false /* full gc */);
4034       increment_gc_time_stamp();
4035 
4036       verify_before_gc();
4037 
4038       check_bitmaps("GC Start");
4039 
4040       COMPILER2_PRESENT(DerivedPointerTable::clear());


4041 
4042       // Please see comment in g1CollectedHeap.hpp and
4043       // G1CollectedHeap::ref_processing_init() to see how
4044       // reference processing currently works in G1.
4045 
4046       // Enable discovery in the STW reference processor
4047       ref_processor_stw()->enable_discovery();
4048 
4049       {
4050         // We want to temporarily turn off discovery by the
4051         // CM ref processor, if necessary, and turn it back on
4052         // on again later if we do. Using a scoped
4053         // NoRefDiscovery object will do this.
4054         NoRefDiscovery no_cm_discovery(ref_processor_cm());
4055 
4056         // Forget the current alloc region (we might even choose it to be part
4057         // of the collection set!).
4058         _allocator->release_mutator_alloc_region();
4059 
4060         // We should call this after we retire the mutator alloc
4061         // region(s) so that all the ALLOC / RETIRE events are generated
4062         // before the start GC event.
4063         _hr_printer.start_gc(false /* full */, (size_t) total_collections());
4064 
4065         // This timing is only used by the ergonomics to handle our pause target.
4066         // It is unclear why this should not include the full pause. We will
4067         // investigate this in CR 7178365.
4068         //
4069         // Preserving the old comment here if that helps the investigation:
4070         //
4071         // The elapsed time induced by the start time below deliberately elides
4072         // the possible verification above.
4073         double sample_start_time_sec = os::elapsedTime();
4074 
4075         g1_policy()->record_collection_pause_start(sample_start_time_sec);
4076 
4077         if (collector_state()->during_initial_mark_pause()) {
4078           concurrent_mark()->checkpointRootsInitialPre();
4079         }
4080 
4081         double time_remaining_ms = g1_policy()->finalize_young_cset_part(target_pause_time_ms);
4082         g1_policy()->finalize_old_cset_part(time_remaining_ms);
4083 
4084         evacuation_info.set_collectionset_regions(g1_policy()->cset_region_length());
4085 
4086         register_humongous_regions_with_cset();
4087 
4088         assert(check_cset_fast_test(), "Inconsistency in the InCSetState table.");
4089 
4090         _cm->note_start_of_gc();
4091         // We call this after finalize_cset() to
4092         // ensure that the CSet has been finalized.
4093         _cm->verify_no_cset_oops();
4094 
4095         if (_hr_printer.is_active()) {
4096           HeapRegion* hr = g1_policy()->collection_set();
4097           while (hr != NULL) {
4098             _hr_printer.cset(hr);
4099             hr = hr->next_in_collection_set();
4100           }
4101         }
4102 
4103 #ifdef ASSERT
4104         VerifyCSetClosure cl;
4105         collection_set_iterate(&cl);
4106 #endif // ASSERT
4107 
4108         // Initialize the GC alloc regions.
4109         _allocator->init_gc_alloc_regions(evacuation_info);
4110 
4111         G1ParScanThreadStateSet per_thread_states(this, workers()->active_workers(), g1_policy()->young_cset_region_length());
4112         // Actually do the work...
4113         evacuate_collection_set(evacuation_info, &per_thread_states);
4114 
4115         const size_t* surviving_young_words = per_thread_states.surviving_young_words();
4116         free_collection_set(g1_policy()->collection_set(), evacuation_info, surviving_young_words);
4117 
4118         eagerly_reclaim_humongous_regions();
4119 
4120         g1_policy()->clear_collection_set();
4121 
4122         // Start a new incremental collection set for the next pause.
4123         g1_policy()->start_incremental_cset_building();
4124 
4125         clear_cset_fast_test();
4126 
4127         _young_list->reset_sampled_info();
4128 
4129         // Don't check the whole heap at this point as the
4130         // GC alloc regions from this pause have been tagged
4131         // as survivors and moved on to the survivor list.
4132         // Survivor regions will fail the !is_young() check.
4133         assert(check_young_list_empty(false /* check_heap */),
4134           "young list should be empty");
4135 
4136         g1_policy()->record_survivor_regions(_young_list->survivor_length(),
4137                                              _young_list->first_survivor_region(),
4138                                              _young_list->last_survivor_region());
4139 
4140         _young_list->reset_auxilary_lists();
4141 
4142         if (evacuation_failed()) {
4143           set_used(recalculate_used());
4144           if (_archive_allocator != NULL) {
4145             _archive_allocator->clear_used();
4146           }
4147           for (uint i = 0; i < ParallelGCThreads; i++) {
4148             if (_evacuation_failed_info_array[i].has_failed()) {
4149               _gc_tracer_stw->report_evacuation_failed(_evacuation_failed_info_array[i]);
4150             }
4151           }
4152         } else {
4153           // The "used" of the the collection set have already been subtracted
4154           // when they were freed.  Add in the bytes evacuated.
4155           increase_used(g1_policy()->bytes_copied_during_gc());
4156         }
4157 
4158         if (collector_state()->during_initial_mark_pause()) {
4159           // We have to do this before we notify the CM threads that
4160           // they can start working to make sure that all the
4161           // appropriate initialization is done on the CM object.
4162           concurrent_mark()->checkpointRootsInitialPost();
4163           collector_state()->set_mark_in_progress(true);
4164           // Note that we don't actually trigger the CM thread at
4165           // this point. We do that later when we're sure that
4166           // the current thread has completed its logging output.
4167         }
4168 
4169         allocate_dummy_regions();
4170 
4171         _allocator->init_mutator_alloc_region();
4172 
4173         {
4174           size_t expand_bytes = g1_policy()->expansion_amount();
4175           if (expand_bytes > 0) {
4176             size_t bytes_before = capacity();
4177             // No need for an ergo verbose message here,
4178             // expansion_amount() does this when it returns a value > 0.
4179             if (!expand(expand_bytes)) {
4180               // We failed to expand the heap. Cannot do anything about it.
4181             }
4182           }
4183         }
4184 
4185         // We redo the verification but now wrt to the new CSet which
4186         // has just got initialized after the previous CSet was freed.
4187         _cm->verify_no_cset_oops();
4188         _cm->note_end_of_gc();
4189 
4190         // This timing is only used by the ergonomics to handle our pause target.
4191         // It is unclear why this should not include the full pause. We will
4192         // investigate this in CR 7178365.
4193         double sample_end_time_sec = os::elapsedTime();
4194         double pause_time_ms = (sample_end_time_sec - sample_start_time_sec) * MILLIUNITS;
4195         size_t total_cards_scanned = per_thread_states.total_cards_scanned();
4196         g1_policy()->record_collection_pause_end(pause_time_ms, total_cards_scanned);
4197 
4198         evacuation_info.set_collectionset_used_before(g1_policy()->collection_set_bytes_used_before());
4199         evacuation_info.set_bytes_copied(g1_policy()->bytes_copied_during_gc());
4200 
4201         MemoryService::track_memory_usage();
4202 
4203         // In prepare_for_verify() below we'll need to scan the deferred
4204         // update buffers to bring the RSets up-to-date if
4205         // G1HRRSFlushLogBuffersOnVerify has been set. While scanning
4206         // the update buffers we'll probably need to scan cards on the
4207         // regions we just allocated to (i.e., the GC alloc
4208         // regions). However, during the last GC we called
4209         // set_saved_mark() on all the GC alloc regions, so card
4210         // scanning might skip the [saved_mark_word()...top()] area of
4211         // those regions (i.e., the area we allocated objects into
4212         // during the last GC). But it shouldn't. Given that
4213         // saved_mark_word() is conditional on whether the GC time stamp
4214         // on the region is current or not, by incrementing the GC time
4215         // stamp here we invalidate all the GC time stamps on all the
4216         // regions and saved_mark_word() will simply return top() for
4217         // all the regions. This is a nicer way of ensuring this rather
4218         // than iterating over the regions and fixing them. In fact, the
4219         // GC time stamp increment here also ensures that
4220         // saved_mark_word() will return top() between pauses, i.e.,
4221         // during concurrent refinement. So we don't need the
4222         // is_gc_active() check to decided which top to use when
4223         // scanning cards (see CR 7039627).
4224         increment_gc_time_stamp();
4225 
4226         verify_after_gc();
4227         check_bitmaps("GC End");
4228 
4229         assert(!ref_processor_stw()->discovery_enabled(), "Postcondition");
4230         ref_processor_stw()->verify_no_references_recorded();
4231 
4232         // CM reference discovery will be re-enabled if necessary.
4233       }
4234 
4235       // We should do this after we potentially expand the heap so
4236       // that all the COMMIT events are generated before the end GC
4237       // event, and after we retire the GC alloc regions so that all
4238       // RETIRE events are generated before the end GC event.
4239       _hr_printer.end_gc(false /* full */, (size_t) total_collections());
4240 
4241 #ifdef TRACESPINNING
4242       ParallelTaskTerminator::print_termination_counts();
4243 #endif
4244 
4245       gc_epilogue(false);
4246     }
4247 
4248     // Print the remainder of the GC log output.
4249     log_gc_footer(os::elapsedTime() - pause_start_sec);
4250 
4251     // It is not yet to safe to tell the concurrent mark to
4252     // start as we have some optional output below. We don't want the
4253     // output from the concurrent mark thread interfering with this
4254     // logging output either.
4255 
4256     _hrm.verify_optional();
4257     verify_region_sets_optional();
4258 
4259     TASKQUEUE_STATS_ONLY(if (PrintTaskqueue) print_taskqueue_stats());
4260     TASKQUEUE_STATS_ONLY(reset_taskqueue_stats());
4261 
4262     print_heap_after_gc();
4263     trace_heap_after_gc(_gc_tracer_stw);
4264 
4265     // We must call G1MonitoringSupport::update_sizes() in the same scoping level
4266     // as an active TraceMemoryManagerStats object (i.e. before the destructor for the
4267     // TraceMemoryManagerStats is called) so that the G1 memory pools are updated
4268     // before any GC notifications are raised.
4269     g1mm()->update_sizes();
4270 
4271     _gc_tracer_stw->report_evacuation_info(&evacuation_info);
4272     _gc_tracer_stw->report_tenuring_threshold(_g1_policy->tenuring_threshold());
4273     _gc_timer_stw->register_gc_end();
4274     _gc_tracer_stw->report_gc_end(_gc_timer_stw->gc_end(), _gc_timer_stw->time_partitions());
4275   }
4276   // It should now be safe to tell the concurrent mark thread to start
4277   // without its logging output interfering with the logging output
4278   // that came from the pause.
4279 
4280   if (should_start_conc_mark) {
4281     // CAUTION: after the doConcurrentMark() call below,
4282     // the concurrent marking thread(s) could be running
4283     // concurrently with us. Make sure that anything after
4284     // this point does not assume that we are the only GC thread
4285     // running. Note: of course, the actual marking work will
4286     // not start until the safepoint itself is released in
4287     // SuspendibleThreadSet::desynchronize().
4288     doConcurrentMark();
4289   }
4290 
4291   return true;
4292 }
4293 
4294 void G1CollectedHeap::remove_self_forwarding_pointers() {
4295   double remove_self_forwards_start = os::elapsedTime();
4296 
4297   G1ParRemoveSelfForwardPtrsTask rsfp_task;
4298   workers()->run_task(&rsfp_task);
4299 
4300   // Now restore saved marks, if any.
4301   for (uint i = 0; i < ParallelGCThreads; i++) {
4302     OopAndMarkOopStack& cur = _preserved_objs[i];
4303     while (!cur.is_empty()) {
4304       OopAndMarkOop elem = cur.pop();
4305       elem.set_mark();
4306     }
4307     cur.clear(true);
4308   }
4309 
4310   g1_policy()->phase_times()->record_evac_fail_remove_self_forwards((os::elapsedTime() - remove_self_forwards_start) * 1000.0);
4311 }
4312 
4313 void G1CollectedHeap::preserve_mark_during_evac_failure(uint worker_id, oop obj, markOop m) {
4314   if (!_evacuation_failed) {
4315     _evacuation_failed = true;
4316   }
4317 
4318   _evacuation_failed_info_array[worker_id].register_copy_failure(obj->size());
4319 
4320   // We want to call the "for_promotion_failure" version only in the
4321   // case of a promotion failure.
4322   if (m->must_be_preserved_for_promotion_failure(obj)) {
4323     OopAndMarkOop elem(obj, m);
4324     _preserved_objs[worker_id].push(elem);
4325   }
4326 }
4327 
4328 void G1ParCopyHelper::mark_object(oop obj) {
4329   assert(!_g1->heap_region_containing(obj)->in_collection_set(), "should not mark objects in the CSet");
4330 
4331   // We know that the object is not moving so it's safe to read its size.
4332   _cm->grayRoot(obj, (size_t) obj->size(), _worker_id);
4333 }
4334 
4335 void G1ParCopyHelper::mark_forwarded_object(oop from_obj, oop to_obj) {
4336   assert(from_obj->is_forwarded(), "from obj should be forwarded");
4337   assert(from_obj->forwardee() == to_obj, "to obj should be the forwardee");
4338   assert(from_obj != to_obj, "should not be self-forwarded");
4339 
4340   assert(_g1->heap_region_containing(from_obj)->in_collection_set(), "from obj should be in the CSet");
4341   assert(!_g1->heap_region_containing(to_obj)->in_collection_set(), "should not mark objects in the CSet");
4342 
4343   // The object might be in the process of being copied by another
4344   // worker so we cannot trust that its to-space image is
4345   // well-formed. So we have to read its size from its from-space
4346   // image which we know should not be changing.
4347   _cm->grayRoot(to_obj, (size_t) from_obj->size(), _worker_id);
4348 }
4349 
4350 template <class T>
4351 void G1ParCopyHelper::do_klass_barrier(T* p, oop new_obj) {
4352   if (_g1->heap_region_containing_raw(new_obj)->is_young()) {
4353     _scanned_klass->record_modified_oops();
4354   }
4355 }
4356 
4357 template <G1Barrier barrier, G1Mark do_mark_object>
4358 template <class T>
4359 void G1ParCopyClosure<barrier, do_mark_object>::do_oop_work(T* p) {
4360   T heap_oop = oopDesc::load_heap_oop(p);
4361 
4362   if (oopDesc::is_null(heap_oop)) {
4363     return;
4364   }
4365 
4366   oop obj = oopDesc::decode_heap_oop_not_null(heap_oop);
4367 
4368   assert(_worker_id == _par_scan_state->worker_id(), "sanity");
4369 
4370   const InCSetState state = _g1->in_cset_state(obj);
4371   if (state.is_in_cset()) {
4372     oop forwardee;
4373     markOop m = obj->mark();
4374     if (m->is_marked()) {
4375       forwardee = (oop) m->decode_pointer();
4376     } else {
4377       forwardee = _par_scan_state->copy_to_survivor_space(state, obj, m);
4378     }
4379     assert(forwardee != NULL, "forwardee should not be NULL");
4380     oopDesc::encode_store_heap_oop(p, forwardee);
4381     if (do_mark_object != G1MarkNone && forwardee != obj) {
4382       // If the object is self-forwarded we don't need to explicitly
4383       // mark it, the evacuation failure protocol will do so.
4384       mark_forwarded_object(obj, forwardee);
4385     }
4386 
4387     if (barrier == G1BarrierKlass) {
4388       do_klass_barrier(p, forwardee);
4389     }
4390   } else {
4391     if (state.is_humongous()) {
4392       _g1->set_humongous_is_live(obj);
4393     }
4394     // The object is not in collection set. If we're a root scanning
4395     // closure during an initial mark pause then attempt to mark the object.
4396     if (do_mark_object == G1MarkFromRoot) {
4397       mark_object(obj);
4398     }
4399   }
4400 }
4401 
4402 class G1ParEvacuateFollowersClosure : public VoidClosure {
4403 private:
4404   double _start_term;
4405   double _term_time;
4406   size_t _term_attempts;
4407 
4408   void start_term_time() { _term_attempts++; _start_term = os::elapsedTime(); }
4409   void end_term_time() { _term_time += os::elapsedTime() - _start_term; }
4410 protected:
4411   G1CollectedHeap*              _g1h;
4412   G1ParScanThreadState*         _par_scan_state;
4413   RefToScanQueueSet*            _queues;
4414   ParallelTaskTerminator*       _terminator;
4415 
4416   G1ParScanThreadState*   par_scan_state() { return _par_scan_state; }
4417   RefToScanQueueSet*      queues()         { return _queues; }
4418   ParallelTaskTerminator* terminator()     { return _terminator; }
4419 
4420 public:
4421   G1ParEvacuateFollowersClosure(G1CollectedHeap* g1h,
4422                                 G1ParScanThreadState* par_scan_state,
4423                                 RefToScanQueueSet* queues,
4424                                 ParallelTaskTerminator* terminator)
4425     : _g1h(g1h), _par_scan_state(par_scan_state),
4426       _queues(queues), _terminator(terminator),
4427       _start_term(0.0), _term_time(0.0), _term_attempts(0) {}
4428 
4429   void do_void();
4430 
4431   double term_time() const { return _term_time; }
4432   size_t term_attempts() const { return _term_attempts; }
4433 
4434 private:
4435   inline bool offer_termination();
4436 };
4437 
4438 bool G1ParEvacuateFollowersClosure::offer_termination() {
4439   G1ParScanThreadState* const pss = par_scan_state();
4440   start_term_time();
4441   const bool res = terminator()->offer_termination();
4442   end_term_time();
4443   return res;
4444 }
4445 
4446 void G1ParEvacuateFollowersClosure::do_void() {
4447   G1ParScanThreadState* const pss = par_scan_state();
4448   pss->trim_queue();
4449   do {
4450     pss->steal_and_trim_queue(queues());
4451   } while (!offer_termination());
4452 }
4453 
4454 class G1KlassScanClosure : public KlassClosure {
4455  G1ParCopyHelper* _closure;
4456  bool             _process_only_dirty;
4457  int              _count;
4458  public:
4459   G1KlassScanClosure(G1ParCopyHelper* closure, bool process_only_dirty)
4460       : _process_only_dirty(process_only_dirty), _closure(closure), _count(0) {}
4461   void do_klass(Klass* klass) {
4462     // If the klass has not been dirtied we know that there's
4463     // no references into  the young gen and we can skip it.
4464    if (!_process_only_dirty || klass->has_modified_oops()) {
4465       // Clean the klass since we're going to scavenge all the metadata.
4466       klass->clear_modified_oops();
4467 
4468       // Tell the closure that this klass is the Klass to scavenge
4469       // and is the one to dirty if oops are left pointing into the young gen.
4470       _closure->set_scanned_klass(klass);
4471 
4472       klass->oops_do(_closure);
4473 
4474       _closure->set_scanned_klass(NULL);
4475     }
4476     _count++;
4477   }
4478 };
4479 
4480 class G1ParTask : public AbstractGangTask {
4481 protected:
4482   G1CollectedHeap*         _g1h;
4483   G1ParScanThreadStateSet* _pss;
4484   RefToScanQueueSet*       _queues;
4485   G1RootProcessor*         _root_processor;
4486   ParallelTaskTerminator   _terminator;
4487   uint                     _n_workers;
4488 
4489 public:
4490   G1ParTask(G1CollectedHeap* g1h, G1ParScanThreadStateSet* per_thread_states, RefToScanQueueSet *task_queues, G1RootProcessor* root_processor, uint n_workers)
4491     : AbstractGangTask("G1 collection"),
4492       _g1h(g1h),
4493       _pss(per_thread_states),
4494       _queues(task_queues),
4495       _root_processor(root_processor),
4496       _terminator(n_workers, _queues),
4497       _n_workers(n_workers)
4498   {}
4499 
4500   RefToScanQueueSet* queues() { return _queues; }
4501 
4502   RefToScanQueue *work_queue(int i) {
4503     return queues()->queue(i);
4504   }
4505 
4506   ParallelTaskTerminator* terminator() { return &_terminator; }
4507 
4508   // Helps out with CLD processing.
4509   //
4510   // During InitialMark we need to:
4511   // 1) Scavenge all CLDs for the young GC.
4512   // 2) Mark all objects directly reachable from strong CLDs.
4513   template <G1Mark do_mark_object>
4514   class G1CLDClosure : public CLDClosure {
4515     G1ParCopyClosure<G1BarrierNone,  do_mark_object>* _oop_closure;
4516     G1ParCopyClosure<G1BarrierKlass, do_mark_object>  _oop_in_klass_closure;
4517     G1KlassScanClosure                                _klass_in_cld_closure;
4518     bool                                              _claim;
4519 
4520    public:
4521     G1CLDClosure(G1ParCopyClosure<G1BarrierNone, do_mark_object>* oop_closure,
4522                  bool only_young, bool claim)
4523         : _oop_closure(oop_closure),
4524           _oop_in_klass_closure(oop_closure->g1(),
4525                                 oop_closure->pss()),
4526           _klass_in_cld_closure(&_oop_in_klass_closure, only_young),
4527           _claim(claim) {
4528 
4529     }
4530 
4531     void do_cld(ClassLoaderData* cld) {
4532       cld->oops_do(_oop_closure, &_klass_in_cld_closure, _claim);
4533     }
4534   };
4535 
4536   void work(uint worker_id) {
4537     if (worker_id >= _n_workers) return;  // no work needed this round
4538 
4539     double start_sec = os::elapsedTime();
4540     _g1h->g1_policy()->phase_times()->record_time_secs(G1GCPhaseTimes::GCWorkerStart, worker_id, start_sec);
4541 
4542     {
4543       ResourceMark rm;
4544       HandleMark   hm;
4545 
4546       ReferenceProcessor*             rp = _g1h->ref_processor_stw();
4547 
4548       G1ParScanThreadState*           pss = _pss->state_for_worker(worker_id);
4549       pss->set_ref_processor(rp);
4550 
4551       bool only_young = _g1h->collector_state()->gcs_are_young();
4552 
4553       // Non-IM young GC.
4554       G1ParCopyClosure<G1BarrierNone, G1MarkNone>             scan_only_root_cl(_g1h, pss);
4555       G1CLDClosure<G1MarkNone>                                scan_only_cld_cl(&scan_only_root_cl,
4556                                                                                only_young, // Only process dirty klasses.
4557                                                                                false);     // No need to claim CLDs.
4558       // IM young GC.
4559       //    Strong roots closures.
4560       G1ParCopyClosure<G1BarrierNone, G1MarkFromRoot>         scan_mark_root_cl(_g1h, pss);
4561       G1CLDClosure<G1MarkFromRoot>                            scan_mark_cld_cl(&scan_mark_root_cl,
4562                                                                                false, // Process all klasses.
4563                                                                                true); // Need to claim CLDs.
4564       //    Weak roots closures.
4565       G1ParCopyClosure<G1BarrierNone, G1MarkPromotedFromRoot> scan_mark_weak_root_cl(_g1h, pss);
4566       G1CLDClosure<G1MarkPromotedFromRoot>                    scan_mark_weak_cld_cl(&scan_mark_weak_root_cl,
4567                                                                                     false, // Process all klasses.
4568                                                                                     true); // Need to claim CLDs.
4569 
4570       OopClosure* strong_root_cl;
4571       OopClosure* weak_root_cl;
4572       CLDClosure* strong_cld_cl;
4573       CLDClosure* weak_cld_cl;
4574 
4575       bool trace_metadata = false;
4576 
4577       if (_g1h->collector_state()->during_initial_mark_pause()) {
4578         // We also need to mark copied objects.
4579         strong_root_cl = &scan_mark_root_cl;
4580         strong_cld_cl  = &scan_mark_cld_cl;
4581         if (ClassUnloadingWithConcurrentMark) {
4582           weak_root_cl = &scan_mark_weak_root_cl;
4583           weak_cld_cl  = &scan_mark_weak_cld_cl;
4584           trace_metadata = true;
4585         } else {
4586           weak_root_cl = &scan_mark_root_cl;
4587           weak_cld_cl  = &scan_mark_cld_cl;
4588         }
4589       } else {
4590         strong_root_cl = &scan_only_root_cl;
4591         weak_root_cl   = &scan_only_root_cl;
4592         strong_cld_cl  = &scan_only_cld_cl;
4593         weak_cld_cl    = &scan_only_cld_cl;
4594       }
4595 
4596       double start_strong_roots_sec = os::elapsedTime();
4597       _root_processor->evacuate_roots(strong_root_cl,
4598                                       weak_root_cl,
4599                                       strong_cld_cl,
4600                                       weak_cld_cl,
4601                                       trace_metadata,
4602                                       worker_id);
4603 
4604       G1ParPushHeapRSClosure push_heap_rs_cl(_g1h, pss);
4605       size_t cards_scanned = _g1h->g1_rem_set()->oops_into_collection_set_do(&push_heap_rs_cl,
4606                                                                              weak_root_cl,
4607                                                                              worker_id);
4608 
4609       _pss->add_cards_scanned(worker_id, cards_scanned);
4610 
4611       double strong_roots_sec = os::elapsedTime() - start_strong_roots_sec;
4612 
4613       double term_sec = 0.0;
4614       size_t evac_term_attempts = 0;
4615       {
4616         double start = os::elapsedTime();
4617         G1ParEvacuateFollowersClosure evac(_g1h, pss, _queues, &_terminator);
4618         evac.do_void();
4619 
4620         evac_term_attempts = evac.term_attempts();
4621         term_sec = evac.term_time();
4622         double elapsed_sec = os::elapsedTime() - start;
4623         _g1h->g1_policy()->phase_times()->add_time_secs(G1GCPhaseTimes::ObjCopy, worker_id, elapsed_sec - term_sec);
4624         _g1h->g1_policy()->phase_times()->record_time_secs(G1GCPhaseTimes::Termination, worker_id, term_sec);
4625         _g1h->g1_policy()->phase_times()->record_thread_work_item(G1GCPhaseTimes::Termination, worker_id, evac_term_attempts);
4626       }
4627 
4628       assert(pss->queue_is_empty(), "should be empty");
4629 
4630       if (PrintTerminationStats) {
4631         MutexLockerEx x(ParGCRareEvent_lock, Mutex::_no_safepoint_check_flag);
4632         size_t lab_waste;
4633         size_t lab_undo_waste;
4634         pss->waste(lab_waste, lab_undo_waste);
4635         _g1h->print_termination_stats(gclog_or_tty,
4636                                       worker_id,
4637                                       (os::elapsedTime() - start_sec) * 1000.0,   /* elapsed time */
4638                                       strong_roots_sec * 1000.0,                  /* strong roots time */
4639                                       term_sec * 1000.0,                          /* evac term time */
4640                                       evac_term_attempts,                         /* evac term attempts */
4641                                       lab_waste,                                  /* alloc buffer waste */
4642                                       lab_undo_waste                              /* undo waste */
4643                                       );
4644       }
4645 
4646       // Close the inner scope so that the ResourceMark and HandleMark
4647       // destructors are executed here and are included as part of the
4648       // "GC Worker Time".
4649     }
4650     _g1h->g1_policy()->phase_times()->record_time_secs(G1GCPhaseTimes::GCWorkerEnd, worker_id, os::elapsedTime());
4651   }
4652 };
4653 
4654 void G1CollectedHeap::print_termination_stats_hdr(outputStream* const st) {
4655   st->print_raw_cr("GC Termination Stats");
4656   st->print_raw_cr("     elapsed  --strong roots-- -------termination------- ------waste (KiB)------");
4657   st->print_raw_cr("thr     ms        ms      %        ms      %    attempts  total   alloc    undo");
4658   st->print_raw_cr("--- --------- --------- ------ --------- ------ -------- ------- ------- -------");
4659 }
4660 
4661 void G1CollectedHeap::print_termination_stats(outputStream* const st,
4662                                               uint worker_id,
4663                                               double elapsed_ms,
4664                                               double strong_roots_ms,
4665                                               double term_ms,
4666                                               size_t term_attempts,
4667                                               size_t alloc_buffer_waste,
4668                                               size_t undo_waste) const {
4669   st->print_cr("%3d %9.2f %9.2f %6.2f "
4670                "%9.2f %6.2f " SIZE_FORMAT_W(8) " "
4671                SIZE_FORMAT_W(7) " " SIZE_FORMAT_W(7) " " SIZE_FORMAT_W(7),
4672                worker_id, elapsed_ms, strong_roots_ms, strong_roots_ms * 100 / elapsed_ms,
4673                term_ms, term_ms * 100 / elapsed_ms, term_attempts,
4674                (alloc_buffer_waste + undo_waste) * HeapWordSize / K,
4675                alloc_buffer_waste * HeapWordSize / K,
4676                undo_waste * HeapWordSize / K);
4677 }
4678 
4679 class G1StringSymbolTableUnlinkTask : public AbstractGangTask {
4680 private:
4681   BoolObjectClosure* _is_alive;
4682   int _initial_string_table_size;
4683   int _initial_symbol_table_size;
4684 
4685   bool  _process_strings;
4686   int _strings_processed;
4687   int _strings_removed;
4688 
4689   bool  _process_symbols;
4690   int _symbols_processed;
4691   int _symbols_removed;
4692 
4693 public:
4694   G1StringSymbolTableUnlinkTask(BoolObjectClosure* is_alive, bool process_strings, bool process_symbols) :
4695     AbstractGangTask("String/Symbol Unlinking"),
4696     _is_alive(is_alive),
4697     _process_strings(process_strings), _strings_processed(0), _strings_removed(0),
4698     _process_symbols(process_symbols), _symbols_processed(0), _symbols_removed(0) {
4699 
4700     _initial_string_table_size = StringTable::the_table()->table_size();
4701     _initial_symbol_table_size = SymbolTable::the_table()->table_size();
4702     if (process_strings) {
4703       StringTable::clear_parallel_claimed_index();
4704     }
4705     if (process_symbols) {
4706       SymbolTable::clear_parallel_claimed_index();
4707     }
4708   }
4709 
4710   ~G1StringSymbolTableUnlinkTask() {
4711     guarantee(!_process_strings || StringTable::parallel_claimed_index() >= _initial_string_table_size,
4712               err_msg("claim value %d after unlink less than initial string table size %d",
4713                       StringTable::parallel_claimed_index(), _initial_string_table_size));
4714     guarantee(!_process_symbols || SymbolTable::parallel_claimed_index() >= _initial_symbol_table_size,
4715               err_msg("claim value %d after unlink less than initial symbol table size %d",
4716                       SymbolTable::parallel_claimed_index(), _initial_symbol_table_size));
4717 
4718     if (G1TraceStringSymbolTableScrubbing) {
4719       gclog_or_tty->print_cr("Cleaned string and symbol table, "
4720                              "strings: " SIZE_FORMAT " processed, " SIZE_FORMAT " removed, "
4721                              "symbols: " SIZE_FORMAT " processed, " SIZE_FORMAT " removed",
4722                              strings_processed(), strings_removed(),
4723                              symbols_processed(), symbols_removed());
4724     }
4725   }
4726 
4727   void work(uint worker_id) {
4728     int strings_processed = 0;
4729     int strings_removed = 0;
4730     int symbols_processed = 0;
4731     int symbols_removed = 0;
4732     if (_process_strings) {
4733       StringTable::possibly_parallel_unlink(_is_alive, &strings_processed, &strings_removed);
4734       Atomic::add(strings_processed, &_strings_processed);
4735       Atomic::add(strings_removed, &_strings_removed);
4736     }
4737     if (_process_symbols) {
4738       SymbolTable::possibly_parallel_unlink(&symbols_processed, &symbols_removed);
4739       Atomic::add(symbols_processed, &_symbols_processed);
4740       Atomic::add(symbols_removed, &_symbols_removed);
4741     }
4742   }
4743 
4744   size_t strings_processed() const { return (size_t)_strings_processed; }
4745   size_t strings_removed()   const { return (size_t)_strings_removed; }
4746 
4747   size_t symbols_processed() const { return (size_t)_symbols_processed; }
4748   size_t symbols_removed()   const { return (size_t)_symbols_removed; }
4749 };
4750 
4751 class G1CodeCacheUnloadingTask VALUE_OBJ_CLASS_SPEC {
4752 private:
4753   static Monitor* _lock;
4754 
4755   BoolObjectClosure* const _is_alive;
4756   const bool               _unloading_occurred;
4757   const uint               _num_workers;
4758 
4759   // Variables used to claim nmethods.
4760   nmethod* _first_nmethod;
4761   volatile nmethod* _claimed_nmethod;
4762 
4763   // The list of nmethods that need to be processed by the second pass.
4764   volatile nmethod* _postponed_list;
4765   volatile uint     _num_entered_barrier;
4766 
4767  public:
4768   G1CodeCacheUnloadingTask(uint num_workers, BoolObjectClosure* is_alive, bool unloading_occurred) :
4769       _is_alive(is_alive),
4770       _unloading_occurred(unloading_occurred),
4771       _num_workers(num_workers),
4772       _first_nmethod(NULL),
4773       _claimed_nmethod(NULL),
4774       _postponed_list(NULL),
4775       _num_entered_barrier(0)
4776   {
4777     nmethod::increase_unloading_clock();
4778     // Get first alive nmethod
4779     NMethodIterator iter = NMethodIterator();
4780     if(iter.next_alive()) {
4781       _first_nmethod = iter.method();
4782     }
4783     _claimed_nmethod = (volatile nmethod*)_first_nmethod;
4784   }
4785 
4786   ~G1CodeCacheUnloadingTask() {
4787     CodeCache::verify_clean_inline_caches();
4788 
4789     CodeCache::set_needs_cache_clean(false);
4790     guarantee(CodeCache::scavenge_root_nmethods() == NULL, "Must be");
4791 
4792     CodeCache::verify_icholder_relocations();
4793   }
4794 
4795  private:
4796   void add_to_postponed_list(nmethod* nm) {
4797       nmethod* old;
4798       do {
4799         old = (nmethod*)_postponed_list;
4800         nm->set_unloading_next(old);
4801       } while ((nmethod*)Atomic::cmpxchg_ptr(nm, &_postponed_list, old) != old);
4802   }
4803 
4804   void clean_nmethod(nmethod* nm) {
4805     bool postponed = nm->do_unloading_parallel(_is_alive, _unloading_occurred);
4806 
4807     if (postponed) {
4808       // This nmethod referred to an nmethod that has not been cleaned/unloaded yet.
4809       add_to_postponed_list(nm);
4810     }
4811 
4812     // Mark that this thread has been cleaned/unloaded.
4813     // After this call, it will be safe to ask if this nmethod was unloaded or not.
4814     nm->set_unloading_clock(nmethod::global_unloading_clock());
4815   }
4816 
4817   void clean_nmethod_postponed(nmethod* nm) {
4818     nm->do_unloading_parallel_postponed(_is_alive, _unloading_occurred);
4819   }
4820 
4821   static const int MaxClaimNmethods = 16;
4822 
4823   void claim_nmethods(nmethod** claimed_nmethods, int *num_claimed_nmethods) {
4824     nmethod* first;
4825     NMethodIterator last;
4826 
4827     do {
4828       *num_claimed_nmethods = 0;
4829 
4830       first = (nmethod*)_claimed_nmethod;
4831       last = NMethodIterator(first);
4832 
4833       if (first != NULL) {
4834 
4835         for (int i = 0; i < MaxClaimNmethods; i++) {
4836           if (!last.next_alive()) {
4837             break;
4838           }
4839           claimed_nmethods[i] = last.method();
4840           (*num_claimed_nmethods)++;
4841         }
4842       }
4843 
4844     } while ((nmethod*)Atomic::cmpxchg_ptr(last.method(), &_claimed_nmethod, first) != first);
4845   }
4846 
4847   nmethod* claim_postponed_nmethod() {
4848     nmethod* claim;
4849     nmethod* next;
4850 
4851     do {
4852       claim = (nmethod*)_postponed_list;
4853       if (claim == NULL) {
4854         return NULL;
4855       }
4856 
4857       next = claim->unloading_next();
4858 
4859     } while ((nmethod*)Atomic::cmpxchg_ptr(next, &_postponed_list, claim) != claim);
4860 
4861     return claim;
4862   }
4863 
4864  public:
4865   // Mark that we're done with the first pass of nmethod cleaning.
4866   void barrier_mark(uint worker_id) {
4867     MonitorLockerEx ml(_lock, Mutex::_no_safepoint_check_flag);
4868     _num_entered_barrier++;
4869     if (_num_entered_barrier == _num_workers) {
4870       ml.notify_all();
4871     }
4872   }
4873 
4874   // See if we have to wait for the other workers to
4875   // finish their first-pass nmethod cleaning work.
4876   void barrier_wait(uint worker_id) {
4877     if (_num_entered_barrier < _num_workers) {
4878       MonitorLockerEx ml(_lock, Mutex::_no_safepoint_check_flag);
4879       while (_num_entered_barrier < _num_workers) {
4880           ml.wait(Mutex::_no_safepoint_check_flag, 0, false);
4881       }
4882     }
4883   }
4884 
4885   // Cleaning and unloading of nmethods. Some work has to be postponed
4886   // to the second pass, when we know which nmethods survive.
4887   void work_first_pass(uint worker_id) {
4888     // The first nmethods is claimed by the first worker.
4889     if (worker_id == 0 && _first_nmethod != NULL) {
4890       clean_nmethod(_first_nmethod);
4891       _first_nmethod = NULL;
4892     }
4893 
4894     int num_claimed_nmethods;
4895     nmethod* claimed_nmethods[MaxClaimNmethods];
4896 
4897     while (true) {
4898       claim_nmethods(claimed_nmethods, &num_claimed_nmethods);
4899 
4900       if (num_claimed_nmethods == 0) {
4901         break;
4902       }
4903 
4904       for (int i = 0; i < num_claimed_nmethods; i++) {
4905         clean_nmethod(claimed_nmethods[i]);
4906       }
4907     }
4908   }
4909 
4910   void work_second_pass(uint worker_id) {
4911     nmethod* nm;
4912     // Take care of postponed nmethods.
4913     while ((nm = claim_postponed_nmethod()) != NULL) {
4914       clean_nmethod_postponed(nm);
4915     }
4916   }
4917 };
4918 
4919 Monitor* G1CodeCacheUnloadingTask::_lock = new Monitor(Mutex::leaf, "Code Cache Unload lock", false, Monitor::_safepoint_check_never);
4920 
4921 class G1KlassCleaningTask : public StackObj {
4922   BoolObjectClosure*                      _is_alive;
4923   volatile jint                           _clean_klass_tree_claimed;
4924   ClassLoaderDataGraphKlassIteratorAtomic _klass_iterator;
4925 
4926  public:
4927   G1KlassCleaningTask(BoolObjectClosure* is_alive) :
4928       _is_alive(is_alive),
4929       _clean_klass_tree_claimed(0),
4930       _klass_iterator() {
4931   }
4932 
4933  private:
4934   bool claim_clean_klass_tree_task() {
4935     if (_clean_klass_tree_claimed) {
4936       return false;
4937     }
4938 
4939     return Atomic::cmpxchg(1, (jint*)&_clean_klass_tree_claimed, 0) == 0;
4940   }
4941 
4942   InstanceKlass* claim_next_klass() {
4943     Klass* klass;
4944     do {
4945       klass =_klass_iterator.next_klass();
4946     } while (klass != NULL && !klass->oop_is_instance());
4947 
4948     return (InstanceKlass*)klass;
4949   }
4950 
4951 public:
4952 
4953   void clean_klass(InstanceKlass* ik) {
4954     ik->clean_implementors_list(_is_alive);
4955     ik->clean_method_data(_is_alive);
4956 
4957     // G1 specific cleanup work that has
4958     // been moved here to be done in parallel.
4959     ik->clean_dependent_nmethods();
4960   }
4961 
4962   void work() {
4963     ResourceMark rm;
4964 
4965     // One worker will clean the subklass/sibling klass tree.
4966     if (claim_clean_klass_tree_task()) {
4967       Klass::clean_subklass_tree(_is_alive);
4968     }
4969 
4970     // All workers will help cleaning the classes,
4971     InstanceKlass* klass;
4972     while ((klass = claim_next_klass()) != NULL) {
4973       clean_klass(klass);
4974     }
4975   }
4976 };
4977 
4978 // To minimize the remark pause times, the tasks below are done in parallel.
4979 class G1ParallelCleaningTask : public AbstractGangTask {
4980 private:
4981   G1StringSymbolTableUnlinkTask _string_symbol_task;
4982   G1CodeCacheUnloadingTask      _code_cache_task;
4983   G1KlassCleaningTask           _klass_cleaning_task;
4984 
4985 public:
4986   // The constructor is run in the VMThread.
4987   G1ParallelCleaningTask(BoolObjectClosure* is_alive, bool process_strings, bool process_symbols, uint num_workers, bool unloading_occurred) :
4988       AbstractGangTask("Parallel Cleaning"),
4989       _string_symbol_task(is_alive, process_strings, process_symbols),
4990       _code_cache_task(num_workers, is_alive, unloading_occurred),
4991       _klass_cleaning_task(is_alive) {
4992   }
4993 
4994   // The parallel work done by all worker threads.
4995   void work(uint worker_id) {
4996     // Do first pass of code cache cleaning.
4997     _code_cache_task.work_first_pass(worker_id);
4998 
4999     // Let the threads mark that the first pass is done.
5000     _code_cache_task.barrier_mark(worker_id);
5001 
5002     // Clean the Strings and Symbols.
5003     _string_symbol_task.work(worker_id);
5004 
5005     // Wait for all workers to finish the first code cache cleaning pass.
5006     _code_cache_task.barrier_wait(worker_id);
5007 
5008     // Do the second code cache cleaning work, which realize on
5009     // the liveness information gathered during the first pass.
5010     _code_cache_task.work_second_pass(worker_id);
5011 
5012     // Clean all klasses that were not unloaded.
5013     _klass_cleaning_task.work();
5014   }
5015 };
5016 
5017 
5018 void G1CollectedHeap::parallel_cleaning(BoolObjectClosure* is_alive,
5019                                         bool process_strings,
5020                                         bool process_symbols,
5021                                         bool class_unloading_occurred) {
5022   uint n_workers = workers()->active_workers();
5023 
5024   G1ParallelCleaningTask g1_unlink_task(is_alive, process_strings, process_symbols,
5025                                         n_workers, class_unloading_occurred);
5026   workers()->run_task(&g1_unlink_task);
5027 }
5028 
5029 void G1CollectedHeap::unlink_string_and_symbol_table(BoolObjectClosure* is_alive,
5030                                                      bool process_strings, bool process_symbols) {
5031   {
5032     G1StringSymbolTableUnlinkTask g1_unlink_task(is_alive, process_strings, process_symbols);
5033     workers()->run_task(&g1_unlink_task);
5034   }
5035 
5036   if (G1StringDedup::is_enabled()) {
5037     G1StringDedup::unlink(is_alive);
5038   }
5039 }
5040 
5041 class G1RedirtyLoggedCardsTask : public AbstractGangTask {
5042  private:
5043   DirtyCardQueueSet* _queue;
5044  public:
5045   G1RedirtyLoggedCardsTask(DirtyCardQueueSet* queue) : AbstractGangTask("Redirty Cards"), _queue(queue) { }
5046 
5047   virtual void work(uint worker_id) {
5048     G1GCPhaseTimes* phase_times = G1CollectedHeap::heap()->g1_policy()->phase_times();
5049     G1GCParPhaseTimesTracker x(phase_times, G1GCPhaseTimes::RedirtyCards, worker_id);
5050 
5051     RedirtyLoggedCardTableEntryClosure cl;
5052     _queue->par_apply_closure_to_all_completed_buffers(&cl);
5053 
5054     phase_times->record_thread_work_item(G1GCPhaseTimes::RedirtyCards, worker_id, cl.num_processed());
5055   }
5056 };
5057 
5058 void G1CollectedHeap::redirty_logged_cards() {
5059   double redirty_logged_cards_start = os::elapsedTime();
5060 
5061   G1RedirtyLoggedCardsTask redirty_task(&dirty_card_queue_set());
5062   dirty_card_queue_set().reset_for_par_iteration();
5063   workers()->run_task(&redirty_task);
5064 
5065   DirtyCardQueueSet& dcq = JavaThread::dirty_card_queue_set();
5066   dcq.merge_bufferlists(&dirty_card_queue_set());
5067   assert(dirty_card_queue_set().completed_buffers_num() == 0, "All should be consumed");
5068 
5069   g1_policy()->phase_times()->record_redirty_logged_cards_time_ms((os::elapsedTime() - redirty_logged_cards_start) * 1000.0);
5070 }
5071 
5072 // Weak Reference Processing support
5073 
5074 // An always "is_alive" closure that is used to preserve referents.
5075 // If the object is non-null then it's alive.  Used in the preservation
5076 // of referent objects that are pointed to by reference objects
5077 // discovered by the CM ref processor.
5078 class G1AlwaysAliveClosure: public BoolObjectClosure {
5079   G1CollectedHeap* _g1;
5080 public:
5081   G1AlwaysAliveClosure(G1CollectedHeap* g1) : _g1(g1) {}
5082   bool do_object_b(oop p) {
5083     if (p != NULL) {
5084       return true;
5085     }
5086     return false;
5087   }
5088 };
5089 
5090 bool G1STWIsAliveClosure::do_object_b(oop p) {
5091   // An object is reachable if it is outside the collection set,
5092   // or is inside and copied.
5093   return !_g1->is_in_cset(p) || p->is_forwarded();
5094 }
5095 
5096 // Non Copying Keep Alive closure
5097 class G1KeepAliveClosure: public OopClosure {
5098   G1CollectedHeap* _g1;
5099 public:
5100   G1KeepAliveClosure(G1CollectedHeap* g1) : _g1(g1) {}
5101   void do_oop(narrowOop* p) { guarantee(false, "Not needed"); }
5102   void do_oop(oop* p) {
5103     oop obj = *p;
5104     assert(obj != NULL, "the caller should have filtered out NULL values");
5105 
5106     const InCSetState cset_state = _g1->in_cset_state(obj);
5107     if (!cset_state.is_in_cset_or_humongous()) {
5108       return;
5109     }
5110     if (cset_state.is_in_cset()) {
5111       assert( obj->is_forwarded(), "invariant" );
5112       *p = obj->forwardee();
5113     } else {
5114       assert(!obj->is_forwarded(), "invariant" );
5115       assert(cset_state.is_humongous(),
5116              err_msg("Only allowed InCSet state is IsHumongous, but is %d", cset_state.value()));
5117       _g1->set_humongous_is_live(obj);
5118     }
5119   }
5120 };
5121 
5122 // Copying Keep Alive closure - can be called from both
5123 // serial and parallel code as long as different worker
5124 // threads utilize different G1ParScanThreadState instances
5125 // and different queues.
5126 
5127 class G1CopyingKeepAliveClosure: public OopClosure {
5128   G1CollectedHeap*         _g1h;
5129   OopClosure*              _copy_non_heap_obj_cl;
5130   G1ParScanThreadState*    _par_scan_state;
5131 
5132 public:
5133   G1CopyingKeepAliveClosure(G1CollectedHeap* g1h,
5134                             OopClosure* non_heap_obj_cl,
5135                             G1ParScanThreadState* pss):
5136     _g1h(g1h),
5137     _copy_non_heap_obj_cl(non_heap_obj_cl),
5138     _par_scan_state(pss)
5139   {}
5140 
5141   virtual void do_oop(narrowOop* p) { do_oop_work(p); }
5142   virtual void do_oop(      oop* p) { do_oop_work(p); }
5143 
5144   template <class T> void do_oop_work(T* p) {
5145     oop obj = oopDesc::load_decode_heap_oop(p);
5146 
5147     if (_g1h->is_in_cset_or_humongous(obj)) {
5148       // If the referent object has been forwarded (either copied
5149       // to a new location or to itself in the event of an
5150       // evacuation failure) then we need to update the reference
5151       // field and, if both reference and referent are in the G1
5152       // heap, update the RSet for the referent.
5153       //
5154       // If the referent has not been forwarded then we have to keep
5155       // it alive by policy. Therefore we have copy the referent.
5156       //
5157       // If the reference field is in the G1 heap then we can push
5158       // on the PSS queue. When the queue is drained (after each
5159       // phase of reference processing) the object and it's followers
5160       // will be copied, the reference field set to point to the
5161       // new location, and the RSet updated. Otherwise we need to
5162       // use the the non-heap or metadata closures directly to copy
5163       // the referent object and update the pointer, while avoiding
5164       // updating the RSet.
5165 
5166       if (_g1h->is_in_g1_reserved(p)) {
5167         _par_scan_state->push_on_queue(p);
5168       } else {
5169         assert(!Metaspace::contains((const void*)p),
5170                err_msg("Unexpectedly found a pointer from metadata: " PTR_FORMAT, p2i(p)));
5171         _copy_non_heap_obj_cl->do_oop(p);
5172       }
5173     }
5174   }
5175 };
5176 
5177 // Serial drain queue closure. Called as the 'complete_gc'
5178 // closure for each discovered list in some of the
5179 // reference processing phases.
5180 
5181 class G1STWDrainQueueClosure: public VoidClosure {
5182 protected:
5183   G1CollectedHeap* _g1h;
5184   G1ParScanThreadState* _par_scan_state;
5185 
5186   G1ParScanThreadState*   par_scan_state() { return _par_scan_state; }
5187 
5188 public:
5189   G1STWDrainQueueClosure(G1CollectedHeap* g1h, G1ParScanThreadState* pss) :
5190     _g1h(g1h),
5191     _par_scan_state(pss)
5192   { }
5193 
5194   void do_void() {
5195     G1ParScanThreadState* const pss = par_scan_state();
5196     pss->trim_queue();
5197   }
5198 };
5199 
5200 // Parallel Reference Processing closures
5201 
5202 // Implementation of AbstractRefProcTaskExecutor for parallel reference
5203 // processing during G1 evacuation pauses.
5204 
5205 class G1STWRefProcTaskExecutor: public AbstractRefProcTaskExecutor {
5206 private:
5207   G1CollectedHeap*          _g1h;
5208   G1ParScanThreadStateSet*  _pss;
5209   RefToScanQueueSet*        _queues;
5210   WorkGang*                 _workers;
5211   uint                      _active_workers;
5212 
5213 public:
5214   G1STWRefProcTaskExecutor(G1CollectedHeap* g1h,
5215                            G1ParScanThreadStateSet* per_thread_states,
5216                            WorkGang* workers,
5217                            RefToScanQueueSet *task_queues,
5218                            uint n_workers) :
5219     _g1h(g1h),
5220     _pss(per_thread_states),
5221     _queues(task_queues),
5222     _workers(workers),
5223     _active_workers(n_workers)
5224   {
5225     assert(n_workers > 0, "shouldn't call this otherwise");
5226   }
5227 
5228   // Executes the given task using concurrent marking worker threads.
5229   virtual void execute(ProcessTask& task);
5230   virtual void execute(EnqueueTask& task);
5231 };
5232 
5233 // Gang task for possibly parallel reference processing
5234 
5235 class G1STWRefProcTaskProxy: public AbstractGangTask {
5236   typedef AbstractRefProcTaskExecutor::ProcessTask ProcessTask;
5237   ProcessTask&     _proc_task;
5238   G1CollectedHeap* _g1h;
5239   G1ParScanThreadStateSet* _pss;
5240   RefToScanQueueSet* _task_queues;
5241   ParallelTaskTerminator* _terminator;
5242 
5243 public:
5244   G1STWRefProcTaskProxy(ProcessTask& proc_task,
5245                         G1CollectedHeap* g1h,
5246                         G1ParScanThreadStateSet* per_thread_states,
5247                         RefToScanQueueSet *task_queues,
5248                         ParallelTaskTerminator* terminator) :
5249     AbstractGangTask("Process reference objects in parallel"),
5250     _proc_task(proc_task),
5251     _g1h(g1h),
5252     _pss(per_thread_states),
5253     _task_queues(task_queues),
5254     _terminator(terminator)
5255   {}
5256 
5257   virtual void work(uint worker_id) {
5258     // The reference processing task executed by a single worker.
5259     ResourceMark rm;
5260     HandleMark   hm;
5261 
5262     G1STWIsAliveClosure is_alive(_g1h);
5263 
5264     G1ParScanThreadState*          pss = _pss->state_for_worker(worker_id);
5265     pss->set_ref_processor(NULL);
5266 
5267     G1ParScanExtRootClosure        only_copy_non_heap_cl(_g1h, pss);
5268 
5269     G1ParScanAndMarkExtRootClosure copy_mark_non_heap_cl(_g1h, pss);
5270 
5271     OopClosure*                    copy_non_heap_cl = &only_copy_non_heap_cl;
5272 
5273     if (_g1h->collector_state()->during_initial_mark_pause()) {
5274       // We also need to mark copied objects.
5275       copy_non_heap_cl = &copy_mark_non_heap_cl;
5276     }
5277 
5278     // Keep alive closure.
5279     G1CopyingKeepAliveClosure keep_alive(_g1h, copy_non_heap_cl, pss);
5280 
5281     // Complete GC closure
5282     G1ParEvacuateFollowersClosure drain_queue(_g1h, pss, _task_queues, _terminator);
5283 
5284     // Call the reference processing task's work routine.
5285     _proc_task.work(worker_id, is_alive, keep_alive, drain_queue);
5286 
5287     // Note we cannot assert that the refs array is empty here as not all
5288     // of the processing tasks (specifically phase2 - pp2_work) execute
5289     // the complete_gc closure (which ordinarily would drain the queue) so
5290     // the queue may not be empty.
5291   }
5292 };
5293 
5294 // Driver routine for parallel reference processing.
5295 // Creates an instance of the ref processing gang
5296 // task and has the worker threads execute it.
5297 void G1STWRefProcTaskExecutor::execute(ProcessTask& proc_task) {
5298   assert(_workers != NULL, "Need parallel worker threads.");
5299 
5300   ParallelTaskTerminator terminator(_active_workers, _queues);
5301   G1STWRefProcTaskProxy proc_task_proxy(proc_task, _g1h, _pss, _queues, &terminator);
5302 
5303   _workers->run_task(&proc_task_proxy);
5304 }
5305 
5306 // Gang task for parallel reference enqueueing.
5307 
5308 class G1STWRefEnqueueTaskProxy: public AbstractGangTask {
5309   typedef AbstractRefProcTaskExecutor::EnqueueTask EnqueueTask;
5310   EnqueueTask& _enq_task;
5311 
5312 public:
5313   G1STWRefEnqueueTaskProxy(EnqueueTask& enq_task) :
5314     AbstractGangTask("Enqueue reference objects in parallel"),
5315     _enq_task(enq_task)
5316   { }
5317 
5318   virtual void work(uint worker_id) {
5319     _enq_task.work(worker_id);
5320   }
5321 };
5322 
5323 // Driver routine for parallel reference enqueueing.
5324 // Creates an instance of the ref enqueueing gang
5325 // task and has the worker threads execute it.
5326 
5327 void G1STWRefProcTaskExecutor::execute(EnqueueTask& enq_task) {
5328   assert(_workers != NULL, "Need parallel worker threads.");
5329 
5330   G1STWRefEnqueueTaskProxy enq_task_proxy(enq_task);
5331 
5332   _workers->run_task(&enq_task_proxy);
5333 }
5334 
5335 // End of weak reference support closures
5336 
5337 // Abstract task used to preserve (i.e. copy) any referent objects
5338 // that are in the collection set and are pointed to by reference
5339 // objects discovered by the CM ref processor.
5340 
5341 class G1ParPreserveCMReferentsTask: public AbstractGangTask {
5342 protected:
5343   G1CollectedHeap*         _g1h;
5344   G1ParScanThreadStateSet* _pss;
5345   RefToScanQueueSet*       _queues;
5346   ParallelTaskTerminator   _terminator;
5347   uint                     _n_workers;
5348 
5349 public:
5350   G1ParPreserveCMReferentsTask(G1CollectedHeap* g1h, G1ParScanThreadStateSet* per_thread_states, int workers, RefToScanQueueSet *task_queues) :
5351     AbstractGangTask("ParPreserveCMReferents"),
5352     _g1h(g1h),
5353     _pss(per_thread_states),
5354     _queues(task_queues),
5355     _terminator(workers, _queues),
5356     _n_workers(workers)
5357   { }
5358 
5359   void work(uint worker_id) {
5360     ResourceMark rm;
5361     HandleMark   hm;
5362 
5363     G1ParScanThreadState*          pss = _pss->state_for_worker(worker_id);
5364     pss->set_ref_processor(NULL);
5365     assert(pss->queue_is_empty(), "both queue and overflow should be empty");
5366 
5367     G1ParScanExtRootClosure        only_copy_non_heap_cl(_g1h, pss);
5368 
5369     G1ParScanAndMarkExtRootClosure copy_mark_non_heap_cl(_g1h, pss);
5370 
5371     OopClosure*                    copy_non_heap_cl = &only_copy_non_heap_cl;
5372 
5373     if (_g1h->collector_state()->during_initial_mark_pause()) {
5374       // We also need to mark copied objects.
5375       copy_non_heap_cl = &copy_mark_non_heap_cl;
5376     }
5377 
5378     // Is alive closure
5379     G1AlwaysAliveClosure always_alive(_g1h);
5380 
5381     // Copying keep alive closure. Applied to referent objects that need
5382     // to be copied.
5383     G1CopyingKeepAliveClosure keep_alive(_g1h, copy_non_heap_cl, pss);
5384 
5385     ReferenceProcessor* rp = _g1h->ref_processor_cm();
5386 
5387     uint limit = ReferenceProcessor::number_of_subclasses_of_ref() * rp->max_num_q();
5388     uint stride = MIN2(MAX2(_n_workers, 1U), limit);
5389 
5390     // limit is set using max_num_q() - which was set using ParallelGCThreads.
5391     // So this must be true - but assert just in case someone decides to
5392     // change the worker ids.
5393     assert(worker_id < limit, "sanity");
5394     assert(!rp->discovery_is_atomic(), "check this code");
5395 
5396     // Select discovered lists [i, i+stride, i+2*stride,...,limit)
5397     for (uint idx = worker_id; idx < limit; idx += stride) {
5398       DiscoveredList& ref_list = rp->discovered_refs()[idx];
5399 
5400       DiscoveredListIterator iter(ref_list, &keep_alive, &always_alive);
5401       while (iter.has_next()) {
5402         // Since discovery is not atomic for the CM ref processor, we
5403         // can see some null referent objects.
5404         iter.load_ptrs(DEBUG_ONLY(true));
5405         oop ref = iter.obj();
5406 
5407         // This will filter nulls.
5408         if (iter.is_referent_alive()) {
5409           iter.make_referent_alive();
5410         }
5411         iter.move_to_next();
5412       }
5413     }
5414 
5415     // Drain the queue - which may cause stealing
5416     G1ParEvacuateFollowersClosure drain_queue(_g1h, pss, _queues, &_terminator);
5417     drain_queue.do_void();
5418     // Allocation buffers were retired at the end of G1ParEvacuateFollowersClosure
5419     assert(pss->queue_is_empty(), "should be");
5420   }
5421 };
5422 
5423 // Weak Reference processing during an evacuation pause (part 1).
5424 void G1CollectedHeap::process_discovered_references(G1ParScanThreadStateSet* per_thread_states) {
5425   double ref_proc_start = os::elapsedTime();
5426 
5427   ReferenceProcessor* rp = _ref_processor_stw;
5428   assert(rp->discovery_enabled(), "should have been enabled");
5429 
5430   // Any reference objects, in the collection set, that were 'discovered'
5431   // by the CM ref processor should have already been copied (either by
5432   // applying the external root copy closure to the discovered lists, or
5433   // by following an RSet entry).
5434   //
5435   // But some of the referents, that are in the collection set, that these
5436   // reference objects point to may not have been copied: the STW ref
5437   // processor would have seen that the reference object had already
5438   // been 'discovered' and would have skipped discovering the reference,
5439   // but would not have treated the reference object as a regular oop.
5440   // As a result the copy closure would not have been applied to the
5441   // referent object.
5442   //
5443   // We need to explicitly copy these referent objects - the references
5444   // will be processed at the end of remarking.
5445   //
5446   // We also need to do this copying before we process the reference
5447   // objects discovered by the STW ref processor in case one of these
5448   // referents points to another object which is also referenced by an
5449   // object discovered by the STW ref processor.
5450 
5451   uint no_of_gc_workers = workers()->active_workers();
5452 
5453   G1ParPreserveCMReferentsTask keep_cm_referents(this,
5454                                                  per_thread_states,
5455                                                  no_of_gc_workers,
5456                                                  _task_queues);
5457 
5458   workers()->run_task(&keep_cm_referents);
5459 
5460   // Closure to test whether a referent is alive.
5461   G1STWIsAliveClosure is_alive(this);
5462 
5463   // Even when parallel reference processing is enabled, the processing
5464   // of JNI refs is serial and performed serially by the current thread
5465   // rather than by a worker. The following PSS will be used for processing
5466   // JNI refs.
5467 
5468   // Use only a single queue for this PSS.
5469   G1ParScanThreadState*          pss = per_thread_states->state_for_worker(0);
5470   pss->set_ref_processor(NULL);
5471   assert(pss->queue_is_empty(), "pre-condition");
5472 
5473   // We do not embed a reference processor in the copying/scanning
5474   // closures while we're actually processing the discovered
5475   // reference objects.
5476 
5477   G1ParScanExtRootClosure        only_copy_non_heap_cl(this, pss);
5478 
5479   G1ParScanAndMarkExtRootClosure copy_mark_non_heap_cl(this, pss);
5480 
5481   OopClosure*                    copy_non_heap_cl = &only_copy_non_heap_cl;
5482 
5483   if (collector_state()->during_initial_mark_pause()) {
5484     // We also need to mark copied objects.
5485     copy_non_heap_cl = &copy_mark_non_heap_cl;
5486   }
5487 
5488   // Keep alive closure.
5489   G1CopyingKeepAliveClosure keep_alive(this, copy_non_heap_cl, pss);
5490 
5491   // Serial Complete GC closure
5492   G1STWDrainQueueClosure drain_queue(this, pss);
5493 
5494   // Setup the soft refs policy...
5495   rp->setup_policy(false);
5496 
5497   ReferenceProcessorStats stats;
5498   if (!rp->processing_is_mt()) {
5499     // Serial reference processing...
5500     stats = rp->process_discovered_references(&is_alive,
5501                                               &keep_alive,
5502                                               &drain_queue,
5503                                               NULL,
5504                                               _gc_timer_stw,
5505                                               _gc_tracer_stw->gc_id());
5506   } else {
5507     // Parallel reference processing
5508     assert(rp->num_q() == no_of_gc_workers, "sanity");
5509     assert(no_of_gc_workers <= rp->max_num_q(), "sanity");
5510 
5511     G1STWRefProcTaskExecutor par_task_executor(this, per_thread_states, workers(), _task_queues, no_of_gc_workers);
5512     stats = rp->process_discovered_references(&is_alive,
5513                                               &keep_alive,
5514                                               &drain_queue,
5515                                               &par_task_executor,
5516                                               _gc_timer_stw,
5517                                               _gc_tracer_stw->gc_id());
5518   }
5519 
5520   _gc_tracer_stw->report_gc_reference_stats(stats);
5521 
5522   // We have completed copying any necessary live referent objects.
5523   assert(pss->queue_is_empty(), "both queue and overflow should be empty");
5524 
5525   double ref_proc_time = os::elapsedTime() - ref_proc_start;
5526   g1_policy()->phase_times()->record_ref_proc_time(ref_proc_time * 1000.0);
5527 }
5528 
5529 // Weak Reference processing during an evacuation pause (part 2).
5530 void G1CollectedHeap::enqueue_discovered_references(G1ParScanThreadStateSet* per_thread_states) {
5531   double ref_enq_start = os::elapsedTime();
5532 
5533   ReferenceProcessor* rp = _ref_processor_stw;
5534   assert(!rp->discovery_enabled(), "should have been disabled as part of processing");
5535 
5536   // Now enqueue any remaining on the discovered lists on to
5537   // the pending list.
5538   if (!rp->processing_is_mt()) {
5539     // Serial reference processing...
5540     rp->enqueue_discovered_references();
5541   } else {
5542     // Parallel reference enqueueing
5543 
5544     uint n_workers = workers()->active_workers();
5545 
5546     assert(rp->num_q() == n_workers, "sanity");
5547     assert(n_workers <= rp->max_num_q(), "sanity");
5548 
5549     G1STWRefProcTaskExecutor par_task_executor(this, per_thread_states, workers(), _task_queues, n_workers);
5550     rp->enqueue_discovered_references(&par_task_executor);
5551   }
5552 
5553   rp->verify_no_references_recorded();
5554   assert(!rp->discovery_enabled(), "should have been disabled");
5555 
5556   // FIXME
5557   // CM's reference processing also cleans up the string and symbol tables.
5558   // Should we do that here also? We could, but it is a serial operation
5559   // and could significantly increase the pause time.
5560 
5561   double ref_enq_time = os::elapsedTime() - ref_enq_start;
5562   g1_policy()->phase_times()->record_ref_enq_time(ref_enq_time * 1000.0);
5563 }
5564 
5565 void G1CollectedHeap::evacuate_collection_set(EvacuationInfo& evacuation_info, G1ParScanThreadStateSet* per_thread_states) {
5566   _expand_heap_after_alloc_failure = true;
5567   _evacuation_failed = false;
5568 
5569   // Should G1EvacuationFailureALot be in effect for this GC?
5570   NOT_PRODUCT(set_evacuation_failure_alot_for_current_gc();)
5571 
5572   g1_rem_set()->prepare_for_oops_into_collection_set_do();
5573 
5574   // Disable the hot card cache.
5575   G1HotCardCache* hot_card_cache = _cg1r->hot_card_cache();
5576   hot_card_cache->reset_hot_cache_claimed_index();
5577   hot_card_cache->set_use_cache(false);
5578 
5579   const uint n_workers = workers()->active_workers();
5580 
5581   assert(dirty_card_queue_set().completed_buffers_num() == 0, "Should be empty");
5582   double start_par_time_sec = os::elapsedTime();
5583   double end_par_time_sec;
5584 
5585   {
5586     G1RootProcessor root_processor(this, n_workers);
5587     G1ParTask g1_par_task(this, per_thread_states, _task_queues, &root_processor, n_workers);
5588     // InitialMark needs claim bits to keep track of the marked-through CLDs.
5589     if (collector_state()->during_initial_mark_pause()) {
5590       ClassLoaderDataGraph::clear_claimed_marks();
5591     }
5592 
5593     // The individual threads will set their evac-failure closures.
5594     if (PrintTerminationStats) {
5595       print_termination_stats_hdr(gclog_or_tty);
5596     }
5597 
5598     workers()->run_task(&g1_par_task);
5599     end_par_time_sec = os::elapsedTime();
5600 
5601     // Closing the inner scope will execute the destructor
5602     // for the G1RootProcessor object. We record the current
5603     // elapsed time before closing the scope so that time
5604     // taken for the destructor is NOT included in the
5605     // reported parallel time.
5606   }
5607 
5608   G1GCPhaseTimes* phase_times = g1_policy()->phase_times();
5609 
5610   double par_time_ms = (end_par_time_sec - start_par_time_sec) * 1000.0;
5611   phase_times->record_par_time(par_time_ms);
5612 
5613   double code_root_fixup_time_ms =
5614         (os::elapsedTime() - end_par_time_sec) * 1000.0;
5615   phase_times->record_code_root_fixup_time(code_root_fixup_time_ms);
5616 
5617   // Process any discovered reference objects - we have
5618   // to do this _before_ we retire the GC alloc regions
5619   // as we may have to copy some 'reachable' referent
5620   // objects (and their reachable sub-graphs) that were
5621   // not copied during the pause.
5622   process_discovered_references(per_thread_states);
5623 
5624   if (G1StringDedup::is_enabled()) {
5625     double fixup_start = os::elapsedTime();
5626 
5627     G1STWIsAliveClosure is_alive(this);
5628     G1KeepAliveClosure keep_alive(this);
5629     G1StringDedup::unlink_or_oops_do(&is_alive, &keep_alive, true, phase_times);
5630 
5631     double fixup_time_ms = (os::elapsedTime() - fixup_start) * 1000.0;
5632     phase_times->record_string_dedup_fixup_time(fixup_time_ms);
5633   }
5634 
5635   _allocator->release_gc_alloc_regions(evacuation_info);
5636   g1_rem_set()->cleanup_after_oops_into_collection_set_do();
5637 
5638   per_thread_states->flush();
5639 
5640   record_obj_copy_mem_stats();
5641 
5642   // Reset and re-enable the hot card cache.
5643   // Note the counts for the cards in the regions in the
5644   // collection set are reset when the collection set is freed.
5645   hot_card_cache->reset_hot_cache();
5646   hot_card_cache->set_use_cache(true);
5647 
5648   purge_code_root_memory();
5649 
5650   if (evacuation_failed()) {
5651     remove_self_forwarding_pointers();
5652 
5653     // Reset the G1EvacuationFailureALot counters and flags
5654     // Note: the values are reset only when an actual
5655     // evacuation failure occurs.
5656     NOT_PRODUCT(reset_evacuation_should_fail();)
5657   }
5658 
5659   // Enqueue any remaining references remaining on the STW
5660   // reference processor's discovered lists. We need to do
5661   // this after the card table is cleaned (and verified) as
5662   // the act of enqueueing entries on to the pending list
5663   // will log these updates (and dirty their associated
5664   // cards). We need these updates logged to update any
5665   // RSets.
5666   enqueue_discovered_references(per_thread_states);
5667 
5668   redirty_logged_cards();
5669   COMPILER2_PRESENT(DerivedPointerTable::update_pointers());


5670 }
5671 
5672 void G1CollectedHeap::record_obj_copy_mem_stats() {
5673   _gc_tracer_stw->report_evacuation_statistics(create_g1_evac_summary(&_survivor_evac_stats),
5674                                                create_g1_evac_summary(&_old_evac_stats));
5675 }
5676 
5677 void G1CollectedHeap::free_region(HeapRegion* hr,
5678                                   FreeRegionList* free_list,
5679                                   bool par,
5680                                   bool locked) {
5681   assert(!hr->is_free(), "the region should not be free");
5682   assert(!hr->is_empty(), "the region should not be empty");
5683   assert(_hrm.is_available(hr->hrm_index()), "region should be committed");
5684   assert(free_list != NULL, "pre-condition");
5685 
5686   if (G1VerifyBitmaps) {
5687     MemRegion mr(hr->bottom(), hr->end());
5688     concurrent_mark()->clearRangePrevBitmap(mr);
5689   }
5690 
5691   // Clear the card counts for this region.
5692   // Note: we only need to do this if the region is not young
5693   // (since we don't refine cards in young regions).
5694   if (!hr->is_young()) {
5695     _cg1r->hot_card_cache()->reset_card_counts(hr);
5696   }
5697   hr->hr_clear(par, true /* clear_space */, locked /* locked */);
5698   free_list->add_ordered(hr);
5699 }
5700 
5701 void G1CollectedHeap::free_humongous_region(HeapRegion* hr,
5702                                      FreeRegionList* free_list,
5703                                      bool par) {
5704   assert(hr->is_starts_humongous(), "this is only for starts humongous regions");
5705   assert(free_list != NULL, "pre-condition");
5706 
5707   size_t hr_capacity = hr->capacity();
5708   // We need to read this before we make the region non-humongous,
5709   // otherwise the information will be gone.
5710   uint last_index = hr->last_hc_index();
5711   hr->clear_humongous();
5712   free_region(hr, free_list, par);
5713 
5714   uint i = hr->hrm_index() + 1;
5715   while (i < last_index) {
5716     HeapRegion* curr_hr = region_at(i);
5717     assert(curr_hr->is_continues_humongous(), "invariant");
5718     curr_hr->clear_humongous();
5719     free_region(curr_hr, free_list, par);
5720     i += 1;
5721   }
5722 }
5723 
5724 void G1CollectedHeap::remove_from_old_sets(const HeapRegionSetCount& old_regions_removed,
5725                                        const HeapRegionSetCount& humongous_regions_removed) {
5726   if (old_regions_removed.length() > 0 || humongous_regions_removed.length() > 0) {
5727     MutexLockerEx x(OldSets_lock, Mutex::_no_safepoint_check_flag);
5728     _old_set.bulk_remove(old_regions_removed);
5729     _humongous_set.bulk_remove(humongous_regions_removed);
5730   }
5731 
5732 }
5733 
5734 void G1CollectedHeap::prepend_to_freelist(FreeRegionList* list) {
5735   assert(list != NULL, "list can't be null");
5736   if (!list->is_empty()) {
5737     MutexLockerEx x(FreeList_lock, Mutex::_no_safepoint_check_flag);
5738     _hrm.insert_list_into_free_list(list);
5739   }
5740 }
5741 
5742 void G1CollectedHeap::decrement_summary_bytes(size_t bytes) {
5743   decrease_used(bytes);
5744 }
5745 
5746 class G1ParCleanupCTTask : public AbstractGangTask {
5747   G1SATBCardTableModRefBS* _ct_bs;
5748   G1CollectedHeap* _g1h;
5749   HeapRegion* volatile _su_head;
5750 public:
5751   G1ParCleanupCTTask(G1SATBCardTableModRefBS* ct_bs,
5752                      G1CollectedHeap* g1h) :
5753     AbstractGangTask("G1 Par Cleanup CT Task"),
5754     _ct_bs(ct_bs), _g1h(g1h) { }
5755 
5756   void work(uint worker_id) {
5757     HeapRegion* r;
5758     while (r = _g1h->pop_dirty_cards_region()) {
5759       clear_cards(r);
5760     }
5761   }
5762 
5763   void clear_cards(HeapRegion* r) {
5764     // Cards of the survivors should have already been dirtied.
5765     if (!r->is_survivor()) {
5766       _ct_bs->clear(MemRegion(r->bottom(), r->end()));
5767     }
5768   }
5769 };
5770 
5771 #ifndef PRODUCT
5772 class G1VerifyCardTableCleanup: public HeapRegionClosure {
5773   G1CollectedHeap* _g1h;
5774   G1SATBCardTableModRefBS* _ct_bs;
5775 public:
5776   G1VerifyCardTableCleanup(G1CollectedHeap* g1h, G1SATBCardTableModRefBS* ct_bs)
5777     : _g1h(g1h), _ct_bs(ct_bs) { }
5778   virtual bool doHeapRegion(HeapRegion* r) {
5779     if (r->is_survivor()) {
5780       _g1h->verify_dirty_region(r);
5781     } else {
5782       _g1h->verify_not_dirty_region(r);
5783     }
5784     return false;
5785   }
5786 };
5787 
5788 void G1CollectedHeap::verify_not_dirty_region(HeapRegion* hr) {
5789   // All of the region should be clean.
5790   G1SATBCardTableModRefBS* ct_bs = g1_barrier_set();
5791   MemRegion mr(hr->bottom(), hr->end());
5792   ct_bs->verify_not_dirty_region(mr);
5793 }
5794 
5795 void G1CollectedHeap::verify_dirty_region(HeapRegion* hr) {
5796   // We cannot guarantee that [bottom(),end()] is dirty.  Threads
5797   // dirty allocated blocks as they allocate them. The thread that
5798   // retires each region and replaces it with a new one will do a
5799   // maximal allocation to fill in [pre_dummy_top(),end()] but will
5800   // not dirty that area (one less thing to have to do while holding
5801   // a lock). So we can only verify that [bottom(),pre_dummy_top()]
5802   // is dirty.
5803   G1SATBCardTableModRefBS* ct_bs = g1_barrier_set();
5804   MemRegion mr(hr->bottom(), hr->pre_dummy_top());
5805   if (hr->is_young()) {
5806     ct_bs->verify_g1_young_region(mr);
5807   } else {
5808     ct_bs->verify_dirty_region(mr);
5809   }
5810 }
5811 
5812 void G1CollectedHeap::verify_dirty_young_list(HeapRegion* head) {
5813   G1SATBCardTableModRefBS* ct_bs = g1_barrier_set();
5814   for (HeapRegion* hr = head; hr != NULL; hr = hr->get_next_young_region()) {
5815     verify_dirty_region(hr);
5816   }
5817 }
5818 
5819 void G1CollectedHeap::verify_dirty_young_regions() {
5820   verify_dirty_young_list(_young_list->first_region());
5821 }
5822 
5823 bool G1CollectedHeap::verify_no_bits_over_tams(const char* bitmap_name, CMBitMapRO* bitmap,
5824                                                HeapWord* tams, HeapWord* end) {
5825   guarantee(tams <= end,
5826             err_msg("tams: " PTR_FORMAT " end: " PTR_FORMAT, p2i(tams), p2i(end)));
5827   HeapWord* result = bitmap->getNextMarkedWordAddress(tams, end);
5828   if (result < end) {
5829     gclog_or_tty->cr();
5830     gclog_or_tty->print_cr("## wrong marked address on %s bitmap: " PTR_FORMAT,
5831                            bitmap_name, p2i(result));
5832     gclog_or_tty->print_cr("## %s tams: " PTR_FORMAT " end: " PTR_FORMAT,
5833                            bitmap_name, p2i(tams), p2i(end));
5834     return false;
5835   }
5836   return true;
5837 }
5838 
5839 bool G1CollectedHeap::verify_bitmaps(const char* caller, HeapRegion* hr) {
5840   CMBitMapRO* prev_bitmap = concurrent_mark()->prevMarkBitMap();
5841   CMBitMapRO* next_bitmap = (CMBitMapRO*) concurrent_mark()->nextMarkBitMap();
5842 
5843   HeapWord* bottom = hr->bottom();
5844   HeapWord* ptams  = hr->prev_top_at_mark_start();
5845   HeapWord* ntams  = hr->next_top_at_mark_start();
5846   HeapWord* end    = hr->end();
5847 
5848   bool res_p = verify_no_bits_over_tams("prev", prev_bitmap, ptams, end);
5849 
5850   bool res_n = true;
5851   // We reset mark_in_progress() before we reset _cmThread->in_progress() and in this window
5852   // we do the clearing of the next bitmap concurrently. Thus, we can not verify the bitmap
5853   // if we happen to be in that state.
5854   if (collector_state()->mark_in_progress() || !_cmThread->in_progress()) {
5855     res_n = verify_no_bits_over_tams("next", next_bitmap, ntams, end);
5856   }
5857   if (!res_p || !res_n) {
5858     gclog_or_tty->print_cr("#### Bitmap verification failed for " HR_FORMAT,
5859                            HR_FORMAT_PARAMS(hr));
5860     gclog_or_tty->print_cr("#### Caller: %s", caller);
5861     return false;
5862   }
5863   return true;
5864 }
5865 
5866 void G1CollectedHeap::check_bitmaps(const char* caller, HeapRegion* hr) {
5867   if (!G1VerifyBitmaps) return;
5868 
5869   guarantee(verify_bitmaps(caller, hr), "bitmap verification");
5870 }
5871 
5872 class G1VerifyBitmapClosure : public HeapRegionClosure {
5873 private:
5874   const char* _caller;
5875   G1CollectedHeap* _g1h;
5876   bool _failures;
5877 
5878 public:
5879   G1VerifyBitmapClosure(const char* caller, G1CollectedHeap* g1h) :
5880     _caller(caller), _g1h(g1h), _failures(false) { }
5881 
5882   bool failures() { return _failures; }
5883 
5884   virtual bool doHeapRegion(HeapRegion* hr) {
5885     if (hr->is_continues_humongous()) return false;
5886 
5887     bool result = _g1h->verify_bitmaps(_caller, hr);
5888     if (!result) {
5889       _failures = true;
5890     }
5891     return false;
5892   }
5893 };
5894 
5895 void G1CollectedHeap::check_bitmaps(const char* caller) {
5896   if (!G1VerifyBitmaps) return;
5897 
5898   G1VerifyBitmapClosure cl(caller, this);
5899   heap_region_iterate(&cl);
5900   guarantee(!cl.failures(), "bitmap verification");
5901 }
5902 
5903 class G1CheckCSetFastTableClosure : public HeapRegionClosure {
5904  private:
5905   bool _failures;
5906  public:
5907   G1CheckCSetFastTableClosure() : HeapRegionClosure(), _failures(false) { }
5908 
5909   virtual bool doHeapRegion(HeapRegion* hr) {
5910     uint i = hr->hrm_index();
5911     InCSetState cset_state = (InCSetState) G1CollectedHeap::heap()->_in_cset_fast_test.get_by_index(i);
5912     if (hr->is_humongous()) {
5913       if (hr->in_collection_set()) {
5914         gclog_or_tty->print_cr("\n## humongous region %u in CSet", i);
5915         _failures = true;
5916         return true;
5917       }
5918       if (cset_state.is_in_cset()) {
5919         gclog_or_tty->print_cr("\n## inconsistent cset state %d for humongous region %u", cset_state.value(), i);
5920         _failures = true;
5921         return true;
5922       }
5923       if (hr->is_continues_humongous() && cset_state.is_humongous()) {
5924         gclog_or_tty->print_cr("\n## inconsistent cset state %d for continues humongous region %u", cset_state.value(), i);
5925         _failures = true;
5926         return true;
5927       }
5928     } else {
5929       if (cset_state.is_humongous()) {
5930         gclog_or_tty->print_cr("\n## inconsistent cset state %d for non-humongous region %u", cset_state.value(), i);
5931         _failures = true;
5932         return true;
5933       }
5934       if (hr->in_collection_set() != cset_state.is_in_cset()) {
5935         gclog_or_tty->print_cr("\n## in CSet %d / cset state %d inconsistency for region %u",
5936                                hr->in_collection_set(), cset_state.value(), i);
5937         _failures = true;
5938         return true;
5939       }
5940       if (cset_state.is_in_cset()) {
5941         if (hr->is_young() != (cset_state.is_young())) {
5942           gclog_or_tty->print_cr("\n## is_young %d / cset state %d inconsistency for region %u",
5943                                  hr->is_young(), cset_state.value(), i);
5944           _failures = true;
5945           return true;
5946         }
5947         if (hr->is_old() != (cset_state.is_old())) {
5948           gclog_or_tty->print_cr("\n## is_old %d / cset state %d inconsistency for region %u",
5949                                  hr->is_old(), cset_state.value(), i);
5950           _failures = true;
5951           return true;
5952         }
5953       }
5954     }
5955     return false;
5956   }
5957 
5958   bool failures() const { return _failures; }
5959 };
5960 
5961 bool G1CollectedHeap::check_cset_fast_test() {
5962   G1CheckCSetFastTableClosure cl;
5963   _hrm.iterate(&cl);
5964   return !cl.failures();
5965 }
5966 #endif // PRODUCT
5967 
5968 void G1CollectedHeap::cleanUpCardTable() {
5969   G1SATBCardTableModRefBS* ct_bs = g1_barrier_set();
5970   double start = os::elapsedTime();
5971 
5972   {
5973     // Iterate over the dirty cards region list.
5974     G1ParCleanupCTTask cleanup_task(ct_bs, this);
5975 
5976     workers()->run_task(&cleanup_task);
5977 #ifndef PRODUCT
5978     if (G1VerifyCTCleanup || VerifyAfterGC) {
5979       G1VerifyCardTableCleanup cleanup_verifier(this, ct_bs);
5980       heap_region_iterate(&cleanup_verifier);
5981     }
5982 #endif
5983   }
5984 
5985   double elapsed = os::elapsedTime() - start;
5986   g1_policy()->phase_times()->record_clear_ct_time(elapsed * 1000.0);
5987 }
5988 
5989 void G1CollectedHeap::free_collection_set(HeapRegion* cs_head, EvacuationInfo& evacuation_info, const size_t* surviving_young_words) {
5990   size_t pre_used = 0;
5991   FreeRegionList local_free_list("Local List for CSet Freeing");
5992 
5993   double young_time_ms     = 0.0;
5994   double non_young_time_ms = 0.0;
5995 
5996   // Since the collection set is a superset of the the young list,
5997   // all we need to do to clear the young list is clear its
5998   // head and length, and unlink any young regions in the code below
5999   _young_list->clear();
6000 
6001   G1CollectorPolicy* policy = g1_policy();
6002 
6003   double start_sec = os::elapsedTime();
6004   bool non_young = true;
6005 
6006   HeapRegion* cur = cs_head;
6007   int age_bound = -1;
6008   size_t rs_lengths = 0;
6009 
6010   while (cur != NULL) {
6011     assert(!is_on_master_free_list(cur), "sanity");
6012     if (non_young) {
6013       if (cur->is_young()) {
6014         double end_sec = os::elapsedTime();
6015         double elapsed_ms = (end_sec - start_sec) * 1000.0;
6016         non_young_time_ms += elapsed_ms;
6017 
6018         start_sec = os::elapsedTime();
6019         non_young = false;
6020       }
6021     } else {
6022       if (!cur->is_young()) {
6023         double end_sec = os::elapsedTime();
6024         double elapsed_ms = (end_sec - start_sec) * 1000.0;
6025         young_time_ms += elapsed_ms;
6026 
6027         start_sec = os::elapsedTime();
6028         non_young = true;
6029       }
6030     }
6031 
6032     rs_lengths += cur->rem_set()->occupied_locked();
6033 
6034     HeapRegion* next = cur->next_in_collection_set();
6035     assert(cur->in_collection_set(), "bad CS");
6036     cur->set_next_in_collection_set(NULL);
6037     clear_in_cset(cur);
6038 
6039     if (cur->is_young()) {
6040       int index = cur->young_index_in_cset();
6041       assert(index != -1, "invariant");
6042       assert((uint) index < policy->young_cset_region_length(), "invariant");
6043       size_t words_survived = surviving_young_words[index];
6044       cur->record_surv_words_in_group(words_survived);
6045 
6046       // At this point the we have 'popped' cur from the collection set
6047       // (linked via next_in_collection_set()) but it is still in the
6048       // young list (linked via next_young_region()). Clear the
6049       // _next_young_region field.
6050       cur->set_next_young_region(NULL);
6051     } else {
6052       int index = cur->young_index_in_cset();
6053       assert(index == -1, "invariant");
6054     }
6055 
6056     assert( (cur->is_young() && cur->young_index_in_cset() > -1) ||
6057             (!cur->is_young() && cur->young_index_in_cset() == -1),
6058             "invariant" );
6059 
6060     if (!cur->evacuation_failed()) {
6061       MemRegion used_mr = cur->used_region();
6062 
6063       // And the region is empty.
6064       assert(!used_mr.is_empty(), "Should not have empty regions in a CS.");
6065       pre_used += cur->used();
6066       free_region(cur, &local_free_list, false /* par */, true /* locked */);
6067     } else {
6068       cur->uninstall_surv_rate_group();
6069       if (cur->is_young()) {
6070         cur->set_young_index_in_cset(-1);
6071       }
6072       cur->set_evacuation_failed(false);
6073       // The region is now considered to be old.
6074       cur->set_old();
6075       // Do some allocation statistics accounting. Regions that failed evacuation
6076       // are always made old, so there is no need to update anything in the young
6077       // gen statistics, but we need to update old gen statistics.
6078       size_t used_words = cur->marked_bytes() / HeapWordSize;
6079       _old_evac_stats.add_failure_used_and_waste(used_words, HeapRegion::GrainWords - used_words);
6080       _old_set.add(cur);
6081       evacuation_info.increment_collectionset_used_after(cur->used());
6082     }
6083     cur = next;
6084   }
6085 
6086   evacuation_info.set_regions_freed(local_free_list.length());
6087   policy->record_max_rs_lengths(rs_lengths);
6088   policy->cset_regions_freed();
6089 
6090   double end_sec = os::elapsedTime();
6091   double elapsed_ms = (end_sec - start_sec) * 1000.0;
6092 
6093   if (non_young) {
6094     non_young_time_ms += elapsed_ms;
6095   } else {
6096     young_time_ms += elapsed_ms;
6097   }
6098 
6099   prepend_to_freelist(&local_free_list);
6100   decrement_summary_bytes(pre_used);
6101   policy->phase_times()->record_young_free_cset_time_ms(young_time_ms);
6102   policy->phase_times()->record_non_young_free_cset_time_ms(non_young_time_ms);
6103 }
6104 
6105 class G1FreeHumongousRegionClosure : public HeapRegionClosure {
6106  private:
6107   FreeRegionList* _free_region_list;
6108   HeapRegionSet* _proxy_set;
6109   HeapRegionSetCount _humongous_regions_removed;
6110   size_t _freed_bytes;
6111  public:
6112 
6113   G1FreeHumongousRegionClosure(FreeRegionList* free_region_list) :
6114     _free_region_list(free_region_list), _humongous_regions_removed(), _freed_bytes(0) {
6115   }
6116 
6117   virtual bool doHeapRegion(HeapRegion* r) {
6118     if (!r->is_starts_humongous()) {
6119       return false;
6120     }
6121 
6122     G1CollectedHeap* g1h = G1CollectedHeap::heap();
6123 
6124     oop obj = (oop)r->bottom();
6125     CMBitMap* next_bitmap = g1h->concurrent_mark()->nextMarkBitMap();
6126 
6127     // The following checks whether the humongous object is live are sufficient.
6128     // The main additional check (in addition to having a reference from the roots
6129     // or the young gen) is whether the humongous object has a remembered set entry.
6130     //
6131     // A humongous object cannot be live if there is no remembered set for it
6132     // because:
6133     // - there can be no references from within humongous starts regions referencing
6134     // the object because we never allocate other objects into them.
6135     // (I.e. there are no intra-region references that may be missed by the
6136     // remembered set)
6137     // - as soon there is a remembered set entry to the humongous starts region
6138     // (i.e. it has "escaped" to an old object) this remembered set entry will stay
6139     // until the end of a concurrent mark.
6140     //
6141     // It is not required to check whether the object has been found dead by marking
6142     // or not, in fact it would prevent reclamation within a concurrent cycle, as
6143     // all objects allocated during that time are considered live.
6144     // SATB marking is even more conservative than the remembered set.
6145     // So if at this point in the collection there is no remembered set entry,
6146     // nobody has a reference to it.
6147     // At the start of collection we flush all refinement logs, and remembered sets
6148     // are completely up-to-date wrt to references to the humongous object.
6149     //
6150     // Other implementation considerations:
6151     // - never consider object arrays at this time because they would pose
6152     // considerable effort for cleaning up the the remembered sets. This is
6153     // required because stale remembered sets might reference locations that
6154     // are currently allocated into.
6155     uint region_idx = r->hrm_index();
6156     if (!g1h->is_humongous_reclaim_candidate(region_idx) ||
6157         !r->rem_set()->is_empty()) {
6158 
6159       if (G1TraceEagerReclaimHumongousObjects) {
6160         gclog_or_tty->print_cr("Live humongous region %u size " SIZE_FORMAT " start " PTR_FORMAT " length %u with remset " SIZE_FORMAT " code roots " SIZE_FORMAT " is marked %d reclaim candidate %d type array %d",
6161                                region_idx,
6162                                (size_t)obj->size() * HeapWordSize,
6163                                p2i(r->bottom()),
6164                                r->region_num(),
6165                                r->rem_set()->occupied(),
6166                                r->rem_set()->strong_code_roots_list_length(),
6167                                next_bitmap->isMarked(r->bottom()),
6168                                g1h->is_humongous_reclaim_candidate(region_idx),
6169                                obj->is_typeArray()
6170                               );
6171       }
6172 
6173       return false;
6174     }
6175 
6176     guarantee(obj->is_typeArray(),
6177               err_msg("Only eagerly reclaiming type arrays is supported, but the object "
6178                       PTR_FORMAT " is not.",
6179                       p2i(r->bottom())));
6180 
6181     if (G1TraceEagerReclaimHumongousObjects) {
6182       gclog_or_tty->print_cr("Dead humongous region %u size " SIZE_FORMAT " start " PTR_FORMAT " length %u with remset " SIZE_FORMAT " code roots " SIZE_FORMAT " is marked %d reclaim candidate %d type array %d",
6183                              region_idx,
6184                              (size_t)obj->size() * HeapWordSize,
6185                              p2i(r->bottom()),
6186                              r->region_num(),
6187                              r->rem_set()->occupied(),
6188                              r->rem_set()->strong_code_roots_list_length(),
6189                              next_bitmap->isMarked(r->bottom()),
6190                              g1h->is_humongous_reclaim_candidate(region_idx),
6191                              obj->is_typeArray()
6192                             );
6193     }
6194     // Need to clear mark bit of the humongous object if already set.
6195     if (next_bitmap->isMarked(r->bottom())) {
6196       next_bitmap->clear(r->bottom());
6197     }
6198     _freed_bytes += r->used();
6199     r->set_containing_set(NULL);
6200     _humongous_regions_removed.increment(1u, r->capacity());
6201     g1h->free_humongous_region(r, _free_region_list, false);
6202 
6203     return false;
6204   }
6205 
6206   HeapRegionSetCount& humongous_free_count() {
6207     return _humongous_regions_removed;
6208   }
6209 
6210   size_t bytes_freed() const {
6211     return _freed_bytes;
6212   }
6213 
6214   size_t humongous_reclaimed() const {
6215     return _humongous_regions_removed.length();
6216   }
6217 };
6218 
6219 void G1CollectedHeap::eagerly_reclaim_humongous_regions() {
6220   assert_at_safepoint(true);
6221 
6222   if (!G1EagerReclaimHumongousObjects ||
6223       (!_has_humongous_reclaim_candidates && !G1TraceEagerReclaimHumongousObjects)) {
6224     g1_policy()->phase_times()->record_fast_reclaim_humongous_time_ms(0.0, 0);
6225     return;
6226   }
6227 
6228   double start_time = os::elapsedTime();
6229 
6230   FreeRegionList local_cleanup_list("Local Humongous Cleanup List");
6231 
6232   G1FreeHumongousRegionClosure cl(&local_cleanup_list);
6233   heap_region_iterate(&cl);
6234 
6235   HeapRegionSetCount empty_set;
6236   remove_from_old_sets(empty_set, cl.humongous_free_count());
6237 
6238   G1HRPrinter* hrp = hr_printer();
6239   if (hrp->is_active()) {
6240     FreeRegionListIterator iter(&local_cleanup_list);
6241     while (iter.more_available()) {
6242       HeapRegion* hr = iter.get_next();
6243       hrp->cleanup(hr);
6244     }
6245   }
6246 
6247   prepend_to_freelist(&local_cleanup_list);
6248   decrement_summary_bytes(cl.bytes_freed());
6249 
6250   g1_policy()->phase_times()->record_fast_reclaim_humongous_time_ms((os::elapsedTime() - start_time) * 1000.0,
6251                                                                     cl.humongous_reclaimed());
6252 }
6253 
6254 // This routine is similar to the above but does not record
6255 // any policy statistics or update free lists; we are abandoning
6256 // the current incremental collection set in preparation of a
6257 // full collection. After the full GC we will start to build up
6258 // the incremental collection set again.
6259 // This is only called when we're doing a full collection
6260 // and is immediately followed by the tearing down of the young list.
6261 
6262 void G1CollectedHeap::abandon_collection_set(HeapRegion* cs_head) {
6263   HeapRegion* cur = cs_head;
6264 
6265   while (cur != NULL) {
6266     HeapRegion* next = cur->next_in_collection_set();
6267     assert(cur->in_collection_set(), "bad CS");
6268     cur->set_next_in_collection_set(NULL);
6269     clear_in_cset(cur);
6270     cur->set_young_index_in_cset(-1);
6271     cur = next;
6272   }
6273 }
6274 
6275 void G1CollectedHeap::set_free_regions_coming() {
6276   if (G1ConcRegionFreeingVerbose) {
6277     gclog_or_tty->print_cr("G1ConcRegionFreeing [cm thread] : "
6278                            "setting free regions coming");
6279   }
6280 
6281   assert(!free_regions_coming(), "pre-condition");
6282   _free_regions_coming = true;
6283 }
6284 
6285 void G1CollectedHeap::reset_free_regions_coming() {
6286   assert(free_regions_coming(), "pre-condition");
6287 
6288   {
6289     MutexLockerEx x(SecondaryFreeList_lock, Mutex::_no_safepoint_check_flag);
6290     _free_regions_coming = false;
6291     SecondaryFreeList_lock->notify_all();
6292   }
6293 
6294   if (G1ConcRegionFreeingVerbose) {
6295     gclog_or_tty->print_cr("G1ConcRegionFreeing [cm thread] : "
6296                            "reset free regions coming");
6297   }
6298 }
6299 
6300 void G1CollectedHeap::wait_while_free_regions_coming() {
6301   // Most of the time we won't have to wait, so let's do a quick test
6302   // first before we take the lock.
6303   if (!free_regions_coming()) {
6304     return;
6305   }
6306 
6307   if (G1ConcRegionFreeingVerbose) {
6308     gclog_or_tty->print_cr("G1ConcRegionFreeing [other] : "
6309                            "waiting for free regions");
6310   }
6311 
6312   {
6313     MutexLockerEx x(SecondaryFreeList_lock, Mutex::_no_safepoint_check_flag);
6314     while (free_regions_coming()) {
6315       SecondaryFreeList_lock->wait(Mutex::_no_safepoint_check_flag);
6316     }
6317   }
6318 
6319   if (G1ConcRegionFreeingVerbose) {
6320     gclog_or_tty->print_cr("G1ConcRegionFreeing [other] : "
6321                            "done waiting for free regions");
6322   }
6323 }
6324 
6325 bool G1CollectedHeap::is_old_gc_alloc_region(HeapRegion* hr) {
6326   return _allocator->is_retained_old_region(hr);
6327 }
6328 
6329 void G1CollectedHeap::set_region_short_lived_locked(HeapRegion* hr) {
6330   _young_list->push_region(hr);
6331 }
6332 
6333 class NoYoungRegionsClosure: public HeapRegionClosure {
6334 private:
6335   bool _success;
6336 public:
6337   NoYoungRegionsClosure() : _success(true) { }
6338   bool doHeapRegion(HeapRegion* r) {
6339     if (r->is_young()) {
6340       gclog_or_tty->print_cr("Region [" PTR_FORMAT ", " PTR_FORMAT ") tagged as young",
6341                              p2i(r->bottom()), p2i(r->end()));
6342       _success = false;
6343     }
6344     return false;
6345   }
6346   bool success() { return _success; }
6347 };
6348 
6349 bool G1CollectedHeap::check_young_list_empty(bool check_heap, bool check_sample) {
6350   bool ret = _young_list->check_list_empty(check_sample);
6351 
6352   if (check_heap) {
6353     NoYoungRegionsClosure closure;
6354     heap_region_iterate(&closure);
6355     ret = ret && closure.success();
6356   }
6357 
6358   return ret;
6359 }
6360 
6361 class TearDownRegionSetsClosure : public HeapRegionClosure {
6362 private:
6363   HeapRegionSet *_old_set;
6364 
6365 public:
6366   TearDownRegionSetsClosure(HeapRegionSet* old_set) : _old_set(old_set) { }
6367 
6368   bool doHeapRegion(HeapRegion* r) {
6369     if (r->is_old()) {
6370       _old_set->remove(r);
6371     } else {
6372       // We ignore free regions, we'll empty the free list afterwards.
6373       // We ignore young regions, we'll empty the young list afterwards.
6374       // We ignore humongous regions, we're not tearing down the
6375       // humongous regions set.
6376       assert(r->is_free() || r->is_young() || r->is_humongous(),
6377              "it cannot be another type");
6378     }
6379     return false;
6380   }
6381 
6382   ~TearDownRegionSetsClosure() {
6383     assert(_old_set->is_empty(), "post-condition");
6384   }
6385 };
6386 
6387 void G1CollectedHeap::tear_down_region_sets(bool free_list_only) {
6388   assert_at_safepoint(true /* should_be_vm_thread */);
6389 
6390   if (!free_list_only) {
6391     TearDownRegionSetsClosure cl(&_old_set);
6392     heap_region_iterate(&cl);
6393 
6394     // Note that emptying the _young_list is postponed and instead done as
6395     // the first step when rebuilding the regions sets again. The reason for
6396     // this is that during a full GC string deduplication needs to know if
6397     // a collected region was young or old when the full GC was initiated.
6398   }
6399   _hrm.remove_all_free_regions();
6400 }
6401 
6402 void G1CollectedHeap::increase_used(size_t bytes) {
6403   _summary_bytes_used += bytes;
6404 }
6405 
6406 void G1CollectedHeap::decrease_used(size_t bytes) {
6407   assert(_summary_bytes_used >= bytes,
6408          err_msg("invariant: _summary_bytes_used: " SIZE_FORMAT " should be >= bytes: " SIZE_FORMAT,
6409                  _summary_bytes_used, bytes));
6410   _summary_bytes_used -= bytes;
6411 }
6412 
6413 void G1CollectedHeap::set_used(size_t bytes) {
6414   _summary_bytes_used = bytes;
6415 }
6416 
6417 class RebuildRegionSetsClosure : public HeapRegionClosure {
6418 private:
6419   bool            _free_list_only;
6420   HeapRegionSet*   _old_set;
6421   HeapRegionManager*   _hrm;
6422   size_t          _total_used;
6423 
6424 public:
6425   RebuildRegionSetsClosure(bool free_list_only,
6426                            HeapRegionSet* old_set, HeapRegionManager* hrm) :
6427     _free_list_only(free_list_only),
6428     _old_set(old_set), _hrm(hrm), _total_used(0) {
6429     assert(_hrm->num_free_regions() == 0, "pre-condition");
6430     if (!free_list_only) {
6431       assert(_old_set->is_empty(), "pre-condition");
6432     }
6433   }
6434 
6435   bool doHeapRegion(HeapRegion* r) {
6436     if (r->is_continues_humongous()) {
6437       return false;
6438     }
6439 
6440     if (r->is_empty()) {
6441       // Add free regions to the free list
6442       r->set_free();
6443       r->set_allocation_context(AllocationContext::system());
6444       _hrm->insert_into_free_list(r);
6445     } else if (!_free_list_only) {
6446       assert(!r->is_young(), "we should not come across young regions");
6447 
6448       if (r->is_humongous()) {
6449         // We ignore humongous regions. We left the humongous set unchanged.
6450       } else {
6451         // Objects that were compacted would have ended up on regions
6452         // that were previously old or free.  Archive regions (which are
6453         // old) will not have been touched.
6454         assert(r->is_free() || r->is_old(), "invariant");
6455         // We now consider them old, so register as such. Leave
6456         // archive regions set that way, however, while still adding
6457         // them to the old set.
6458         if (!r->is_archive()) {
6459           r->set_old();
6460         }
6461         _old_set->add(r);
6462       }
6463       _total_used += r->used();
6464     }
6465 
6466     return false;
6467   }
6468 
6469   size_t total_used() {
6470     return _total_used;
6471   }
6472 };
6473 
6474 void G1CollectedHeap::rebuild_region_sets(bool free_list_only) {
6475   assert_at_safepoint(true /* should_be_vm_thread */);
6476 
6477   if (!free_list_only) {
6478     _young_list->empty_list();
6479   }
6480 
6481   RebuildRegionSetsClosure cl(free_list_only, &_old_set, &_hrm);
6482   heap_region_iterate(&cl);
6483 
6484   if (!free_list_only) {
6485     set_used(cl.total_used());
6486     if (_archive_allocator != NULL) {
6487       _archive_allocator->clear_used();
6488     }
6489   }
6490   assert(used_unlocked() == recalculate_used(),
6491          err_msg("inconsistent used_unlocked(), "
6492                  "value: " SIZE_FORMAT " recalculated: " SIZE_FORMAT,
6493                  used_unlocked(), recalculate_used()));
6494 }
6495 
6496 void G1CollectedHeap::set_refine_cte_cl_concurrency(bool concurrent) {
6497   _refine_cte_cl->set_concurrent(concurrent);
6498 }
6499 
6500 bool G1CollectedHeap::is_in_closed_subset(const void* p) const {
6501   HeapRegion* hr = heap_region_containing(p);
6502   return hr->is_in(p);
6503 }
6504 
6505 // Methods for the mutator alloc region
6506 
6507 HeapRegion* G1CollectedHeap::new_mutator_alloc_region(size_t word_size,
6508                                                       bool force) {
6509   assert_heap_locked_or_at_safepoint(true /* should_be_vm_thread */);
6510   assert(!force || g1_policy()->can_expand_young_list(),
6511          "if force is true we should be able to expand the young list");
6512   bool young_list_full = g1_policy()->is_young_list_full();
6513   if (force || !young_list_full) {
6514     HeapRegion* new_alloc_region = new_region(word_size,
6515                                               false /* is_old */,
6516                                               false /* do_expand */);
6517     if (new_alloc_region != NULL) {
6518       set_region_short_lived_locked(new_alloc_region);
6519       _hr_printer.alloc(new_alloc_region, G1HRPrinter::Eden, young_list_full);
6520       check_bitmaps("Mutator Region Allocation", new_alloc_region);
6521       return new_alloc_region;
6522     }
6523   }
6524   return NULL;
6525 }
6526 
6527 void G1CollectedHeap::retire_mutator_alloc_region(HeapRegion* alloc_region,
6528                                                   size_t allocated_bytes) {
6529   assert_heap_locked_or_at_safepoint(true /* should_be_vm_thread */);
6530   assert(alloc_region->is_eden(), "all mutator alloc regions should be eden");
6531 
6532   g1_policy()->add_region_to_incremental_cset_lhs(alloc_region);
6533   increase_used(allocated_bytes);
6534   _hr_printer.retire(alloc_region);
6535   // We update the eden sizes here, when the region is retired,
6536   // instead of when it's allocated, since this is the point that its
6537   // used space has been recored in _summary_bytes_used.
6538   g1mm()->update_eden_size();
6539 }
6540 
6541 // Methods for the GC alloc regions
6542 
6543 HeapRegion* G1CollectedHeap::new_gc_alloc_region(size_t word_size,
6544                                                  uint count,
6545                                                  InCSetState dest) {
6546   assert(FreeList_lock->owned_by_self(), "pre-condition");
6547 
6548   if (count < g1_policy()->max_regions(dest)) {
6549     const bool is_survivor = (dest.is_young());
6550     HeapRegion* new_alloc_region = new_region(word_size,
6551                                               !is_survivor,
6552                                               true /* do_expand */);
6553     if (new_alloc_region != NULL) {
6554       // We really only need to do this for old regions given that we
6555       // should never scan survivors. But it doesn't hurt to do it
6556       // for survivors too.
6557       new_alloc_region->record_timestamp();
6558       if (is_survivor) {
6559         new_alloc_region->set_survivor();
6560         _hr_printer.alloc(new_alloc_region, G1HRPrinter::Survivor);
6561         check_bitmaps("Survivor Region Allocation", new_alloc_region);
6562       } else {
6563         new_alloc_region->set_old();
6564         _hr_printer.alloc(new_alloc_region, G1HRPrinter::Old);
6565         check_bitmaps("Old Region Allocation", new_alloc_region);
6566       }
6567       bool during_im = collector_state()->during_initial_mark_pause();
6568       new_alloc_region->note_start_of_copying(during_im);
6569       return new_alloc_region;
6570     }
6571   }
6572   return NULL;
6573 }
6574 
6575 void G1CollectedHeap::retire_gc_alloc_region(HeapRegion* alloc_region,
6576                                              size_t allocated_bytes,
6577                                              InCSetState dest) {
6578   bool during_im = collector_state()->during_initial_mark_pause();
6579   alloc_region->note_end_of_copying(during_im);
6580   g1_policy()->record_bytes_copied_during_gc(allocated_bytes);
6581   if (dest.is_young()) {
6582     young_list()->add_survivor_region(alloc_region);
6583   } else {
6584     _old_set.add(alloc_region);
6585   }
6586   _hr_printer.retire(alloc_region);
6587 }
6588 
6589 HeapRegion* G1CollectedHeap::alloc_highest_free_region() {
6590   bool expanded = false;
6591   uint index = _hrm.find_highest_free(&expanded);
6592 
6593   if (index != G1_NO_HRM_INDEX) {
6594     if (expanded) {
6595       ergo_verbose1(ErgoHeapSizing,
6596                     "attempt heap expansion",
6597                     ergo_format_reason("requested address range outside heap bounds")
6598                     ergo_format_byte("region size"),
6599                     HeapRegion::GrainWords * HeapWordSize);
6600     }
6601     _hrm.allocate_free_regions_starting_at(index, 1);
6602     return region_at(index);
6603   }
6604   return NULL;
6605 }
6606 
6607 // Heap region set verification
6608 
6609 class VerifyRegionListsClosure : public HeapRegionClosure {
6610 private:
6611   HeapRegionSet*   _old_set;
6612   HeapRegionSet*   _humongous_set;
6613   HeapRegionManager*   _hrm;
6614 
6615 public:
6616   HeapRegionSetCount _old_count;
6617   HeapRegionSetCount _humongous_count;
6618   HeapRegionSetCount _free_count;
6619 
6620   VerifyRegionListsClosure(HeapRegionSet* old_set,
6621                            HeapRegionSet* humongous_set,
6622                            HeapRegionManager* hrm) :
6623     _old_set(old_set), _humongous_set(humongous_set), _hrm(hrm),
6624     _old_count(), _humongous_count(), _free_count(){ }
6625 
6626   bool doHeapRegion(HeapRegion* hr) {
6627     if (hr->is_continues_humongous()) {
6628       return false;
6629     }
6630 
6631     if (hr->is_young()) {
6632       // TODO
6633     } else if (hr->is_starts_humongous()) {
6634       assert(hr->containing_set() == _humongous_set, err_msg("Heap region %u is starts humongous but not in humongous set.", hr->hrm_index()));
6635       _humongous_count.increment(1u, hr->capacity());
6636     } else if (hr->is_empty()) {
6637       assert(_hrm->is_free(hr), err_msg("Heap region %u is empty but not on the free list.", hr->hrm_index()));
6638       _free_count.increment(1u, hr->capacity());
6639     } else if (hr->is_old()) {
6640       assert(hr->containing_set() == _old_set, err_msg("Heap region %u is old but not in the old set.", hr->hrm_index()));
6641       _old_count.increment(1u, hr->capacity());
6642     } else {
6643       // There are no other valid region types. Check for one invalid
6644       // one we can identify: pinned without old or humongous set.
6645       assert(!hr->is_pinned(), err_msg("Heap region %u is pinned but not old (archive) or humongous.", hr->hrm_index()));
6646       ShouldNotReachHere();
6647     }
6648     return false;
6649   }
6650 
6651   void verify_counts(HeapRegionSet* old_set, HeapRegionSet* humongous_set, HeapRegionManager* free_list) {
6652     guarantee(old_set->length() == _old_count.length(), err_msg("Old set count mismatch. Expected %u, actual %u.", old_set->length(), _old_count.length()));
6653     guarantee(old_set->total_capacity_bytes() == _old_count.capacity(), err_msg("Old set capacity mismatch. Expected " SIZE_FORMAT ", actual " SIZE_FORMAT,
6654         old_set->total_capacity_bytes(), _old_count.capacity()));
6655 
6656     guarantee(humongous_set->length() == _humongous_count.length(), err_msg("Hum set count mismatch. Expected %u, actual %u.", humongous_set->length(), _humongous_count.length()));
6657     guarantee(humongous_set->total_capacity_bytes() == _humongous_count.capacity(), err_msg("Hum set capacity mismatch. Expected " SIZE_FORMAT ", actual " SIZE_FORMAT,
6658         humongous_set->total_capacity_bytes(), _humongous_count.capacity()));
6659 
6660     guarantee(free_list->num_free_regions() == _free_count.length(), err_msg("Free list count mismatch. Expected %u, actual %u.", free_list->num_free_regions(), _free_count.length()));
6661     guarantee(free_list->total_capacity_bytes() == _free_count.capacity(), err_msg("Free list capacity mismatch. Expected " SIZE_FORMAT ", actual " SIZE_FORMAT,
6662         free_list->total_capacity_bytes(), _free_count.capacity()));
6663   }
6664 };
6665 
6666 void G1CollectedHeap::verify_region_sets() {
6667   assert_heap_locked_or_at_safepoint(true /* should_be_vm_thread */);
6668 
6669   // First, check the explicit lists.
6670   _hrm.verify();
6671   {
6672     // Given that a concurrent operation might be adding regions to
6673     // the secondary free list we have to take the lock before
6674     // verifying it.
6675     MutexLockerEx x(SecondaryFreeList_lock, Mutex::_no_safepoint_check_flag);
6676     _secondary_free_list.verify_list();
6677   }
6678 
6679   // If a concurrent region freeing operation is in progress it will
6680   // be difficult to correctly attributed any free regions we come
6681   // across to the correct free list given that they might belong to
6682   // one of several (free_list, secondary_free_list, any local lists,
6683   // etc.). So, if that's the case we will skip the rest of the
6684   // verification operation. Alternatively, waiting for the concurrent
6685   // operation to complete will have a non-trivial effect on the GC's
6686   // operation (no concurrent operation will last longer than the
6687   // interval between two calls to verification) and it might hide
6688   // any issues that we would like to catch during testing.
6689   if (free_regions_coming()) {
6690     return;
6691   }
6692 
6693   // Make sure we append the secondary_free_list on the free_list so
6694   // that all free regions we will come across can be safely
6695   // attributed to the free_list.
6696   append_secondary_free_list_if_not_empty_with_lock();
6697 
6698   // Finally, make sure that the region accounting in the lists is
6699   // consistent with what we see in the heap.
6700 
6701   VerifyRegionListsClosure cl(&_old_set, &_humongous_set, &_hrm);
6702   heap_region_iterate(&cl);
6703   cl.verify_counts(&_old_set, &_humongous_set, &_hrm);
6704 }
6705 
6706 // Optimized nmethod scanning
6707 
6708 class RegisterNMethodOopClosure: public OopClosure {
6709   G1CollectedHeap* _g1h;
6710   nmethod* _nm;
6711 
6712   template <class T> void do_oop_work(T* p) {
6713     T heap_oop = oopDesc::load_heap_oop(p);
6714     if (!oopDesc::is_null(heap_oop)) {
6715       oop obj = oopDesc::decode_heap_oop_not_null(heap_oop);
6716       HeapRegion* hr = _g1h->heap_region_containing(obj);
6717       assert(!hr->is_continues_humongous(),
6718              err_msg("trying to add code root " PTR_FORMAT " in continuation of humongous region " HR_FORMAT
6719                      " starting at " HR_FORMAT,
6720                      p2i(_nm), HR_FORMAT_PARAMS(hr), HR_FORMAT_PARAMS(hr->humongous_start_region())));
6721 
6722       // HeapRegion::add_strong_code_root_locked() avoids adding duplicate entries.
6723       hr->add_strong_code_root_locked(_nm);
6724     }
6725   }
6726 
6727 public:
6728   RegisterNMethodOopClosure(G1CollectedHeap* g1h, nmethod* nm) :
6729     _g1h(g1h), _nm(nm) {}
6730 
6731   void do_oop(oop* p)       { do_oop_work(p); }
6732   void do_oop(narrowOop* p) { do_oop_work(p); }
6733 };
6734 
6735 class UnregisterNMethodOopClosure: public OopClosure {
6736   G1CollectedHeap* _g1h;
6737   nmethod* _nm;
6738 
6739   template <class T> void do_oop_work(T* p) {
6740     T heap_oop = oopDesc::load_heap_oop(p);
6741     if (!oopDesc::is_null(heap_oop)) {
6742       oop obj = oopDesc::decode_heap_oop_not_null(heap_oop);
6743       HeapRegion* hr = _g1h->heap_region_containing(obj);
6744       assert(!hr->is_continues_humongous(),
6745              err_msg("trying to remove code root " PTR_FORMAT " in continuation of humongous region " HR_FORMAT
6746                      " starting at " HR_FORMAT,
6747                      p2i(_nm), HR_FORMAT_PARAMS(hr), HR_FORMAT_PARAMS(hr->humongous_start_region())));
6748 
6749       hr->remove_strong_code_root(_nm);
6750     }
6751   }
6752 
6753 public:
6754   UnregisterNMethodOopClosure(G1CollectedHeap* g1h, nmethod* nm) :
6755     _g1h(g1h), _nm(nm) {}
6756 
6757   void do_oop(oop* p)       { do_oop_work(p); }
6758   void do_oop(narrowOop* p) { do_oop_work(p); }
6759 };
6760 
6761 void G1CollectedHeap::register_nmethod(nmethod* nm) {
6762   CollectedHeap::register_nmethod(nm);
6763 
6764   guarantee(nm != NULL, "sanity");
6765   RegisterNMethodOopClosure reg_cl(this, nm);
6766   nm->oops_do(&reg_cl);
6767 }
6768 
6769 void G1CollectedHeap::unregister_nmethod(nmethod* nm) {
6770   CollectedHeap::unregister_nmethod(nm);
6771 
6772   guarantee(nm != NULL, "sanity");
6773   UnregisterNMethodOopClosure reg_cl(this, nm);
6774   nm->oops_do(&reg_cl, true);
6775 }
6776 
6777 void G1CollectedHeap::purge_code_root_memory() {
6778   double purge_start = os::elapsedTime();
6779   G1CodeRootSet::purge();
6780   double purge_time_ms = (os::elapsedTime() - purge_start) * 1000.0;
6781   g1_policy()->phase_times()->record_strong_code_root_purge_time(purge_time_ms);
6782 }
6783 
6784 class RebuildStrongCodeRootClosure: public CodeBlobClosure {
6785   G1CollectedHeap* _g1h;
6786 
6787 public:
6788   RebuildStrongCodeRootClosure(G1CollectedHeap* g1h) :
6789     _g1h(g1h) {}
6790 
6791   void do_code_blob(CodeBlob* cb) {
6792     nmethod* nm = (cb != NULL) ? cb->as_nmethod_or_null() : NULL;
6793     if (nm == NULL) {
6794       return;
6795     }
6796 
6797     if (ScavengeRootsInCode) {
6798       _g1h->register_nmethod(nm);
6799     }
6800   }
6801 };
6802 
6803 void G1CollectedHeap::rebuild_strong_code_roots() {
6804   RebuildStrongCodeRootClosure blob_cl(this);
6805   CodeCache::blobs_do(&blob_cl);
6806 }
--- EOF ---